There’s been quite a bit of uncertainty this season as the Arizona Diamondbacks field one of the youngest lineups in baseball. As the ‘23 season enters its final month, the offense has been filled with promise unlike before. The club has tumbled to a 53-54 losing record after leading the division for a 34-game stretch right up to the All-Star break. Since then, the lineup has struggled to a bottom-ten .304 wOBA offense in 28 games, sporting a league-worst 7-21 record in that stretch. The club is still in the thick of an N.L. Wild Card race for what would be its first playoff berth in six seasons. All-stars Corbin Carroll and shortstop Geraldo Perdomo headline Arizona’s crop of hitters just getting started in the bigs, while catcher Gabriel Moreno and outfielder Dominic Fletcher have also made some noise when called upon. Outfielders Jake McCarthy and Alek Thomas continue to improve in their second full season in the bigs.
Emmanuel Rivera is nearly as new to the bigs as most of his young teammates – only tallying hardly one season’s worth of plate appearances (457) through last year. However, his name didn’t gain as much traction around the league before getting sent down to AAA-Reno earlier this week.
Rivera, an 18th-round draft pick by the Royals in ‘15, was an under-the-radar prospect coming up through Kansas City’s farm system, never being a top-10 prospect in the organization, per MLB Pipeline. After seven years in the minors, he made his MLB debut in June 2021, but he batted to a .641 OPS in a small sample of 93 plate appearances that season. Kansas City gave Rivera another opportunity in 2022, although his playing time dried up quickly when Royals’ premier prospect 3B/SS Bobby Witt Jr. – the second pick in the 2019 draft – reached the bigs. Rivera couldn’t get hot in his limited interviews with KC, but he found a second chance in the bigs with a team that had actually been without a typical third baseman ever since Eduardo Escobar was traded at the deadline before.
In his first 21 games with the Dbacks, he slashed .293/.398/.587 with five homers, which equated to a phenomenal .421 wOBA – the 17th-best (of 264 hitters) during that mid-season span. His hot start took a nosedive for the final 18 games of the season, batting to a dismal .167 wOBA (weighted on-base percentage) – the lowest by far in MLB during that stretch. Throughout his 102 games last season with Kansas City and Arizona, Rivera’s overall numbers, slashing .233/.292/.409 for a 98 OPS+, which is slightly below league-average production, weren’t that exciting on paper. Although, he showed promise at the plate because of his success with three of the core components of a competent hitter.
For one, his plate discipline was displayed, as he swung at a below-average rate of balls (known as Chase rate or O-Swing%). He also made contact with an above-average rate of pitches inside the zone, known as Zone Contact%. Finally, had an above-average Barrel% on batted-ball events. Those stats could look very specific, but hitters who can maintain those three tools at the plate over the course of a full season typically yield productive results. Below is a list of the qualified batters who had an equal or better Chase%, Zone Contact%, and Barrel% than Rivera last year, per Fangraphs. Of the 16 batters who’d met those criteria, 13 were above-average hitters overall in terms of wRC+, an index number measuring offensive production. Unfortunately for Rivera, he was tied for last at a 98 wRC+, which was 2% below the league average.
Rivera made a strong case for the Diamondbacks’ starting third baseman gig this season, but the team ultimately hoped to play it safe by signing 16-year veteran Evan Longoria on a one-year deal. With utilityman Josh Rojas and Longoria, Arizona’s third-base setup looked secure entering this year, but it didn’t pan out that way.
The first half of this ‘23 season was an all-around struggle at the plate for Rojas, who was traded at the trade deadline in a deal for closer Paul Sewald from the Seattle Mariners. The 29-year-old was a bright spot for the ballclub in two frustrating consecutive seasons across 2021 and ‘22 when he accumulated a 4.4 fWAR, tied with Christian Walker for the second-highest (behind Varsho) in the lineup. His defensive versatility served him well in his tenure though, especially at third base. His light-hitting profile always brought concerns about his offensive production, which showed in his putrid .259 wOBA in 200-plus plate appearances this season. Mike Hazen was quick to bring in Rojas’ replacement, as Jace Peterson, 33, was acquired at the deadline from the Oakland Athletics. He profiles a similar player to Rojas offensively and defensively, and he’s under club control through next year on a 2-year, $9.5 million contract.
On the other end, Evan Longoria has performed with mixed results. The 37-year-old is batting to a 117 OPS+ (17% above league average) in 55 games across third-base, DH, and pinch-hitting. However, his current stint on the injured list has been much longer than expected. Longo is still proving his power at 37 years old. His 56.7 hard-hit% (percentage of batted-ball events hit at least 95 mph) is the fifth-highest in baseball – even higher than Vlad Jr, Shohei Ohtani, Ronald Acuña, and many more. Longoria’s strikeout issues worsen a lot versus righties, where his 39.1% K rate is the ninth-highest amongst 247 batters (min. 50 PAs) in righty-on-righty matchups this season. Longoria’s problem with striking out isn’t entirely brand new. Since 2021, Longoria’s been whiffing and K’ing a lot more, which will likely persist. At this point, Longoria is at his best when platooning versus southpaws once he returns from the injured list.
Rivera is having another season where his overall numbers don’t fully reflect what he’s done. Before getting sent down last week, his slash line of .288/.333/.405 for a 102 OPS+ (2% above league average) was decent, but his ‘23 campaign was more encouraging than that.
Rivera was an intriguing batter yet again this year, particularly when he made good contact, which happened a lot. This year, 49.1% of his batted-ball events in the bigs were hit hard (>=95 exit velocity), and 40% of his BBEs were within the sweet-spot range (launch angle between 8 and 32 degrees). Only three hitters of the 274 qualified batters (min. 150 BBEs) posted a higher hard-hit rate and sweet spot percentage than Rivera.
Below is a list of the four players’ hard-hit rate, sweet-spot rate, and isolated power, which measures a batter’s ability to hit for power (extra bases). As shown below, Martinez and Seager both lead the way in MLB in terms of isolated power, while Jung ranks in the top five of hitters, too. However, their results were all much better than Rivera, whose .110 ISO put him in the 14th percentile, ranking well below the league average of a .165 ISO this season.
|ISO (percentile)||Hard-Hit Rate||Sweet-Spot Rate|
Based on the table, Rivera should’ve been getting more extra bases based on hitters with similar hard-hit rates and launch angles, but that isn’t exactly the case. Rivera’s expected slugging percentage, which takes into account a batter’s quality of contact (using exit velocity and launch angle) to more precisely assess one’s power by removing any luck that influences balls in play, suggests that Rivera’s actual power numbers were fairly in line with where he should be ranked and that bad luck isn’t impacting him much here. Rivera’s .406 xSLG was slightly above his actual .382 SLG, but that isn’t significant enough to fully explain the disparity between his impressive contact skills and the disappointing results overall. Expected slugging percentage (xSLG) doesn’t account for the horizontal angle of batted-ball events, which is the main component of Rivera’s game holding him back from being a top hitter in the league.
In an interview regarding Rivera’s demotion before last Saturday’s game, Manager Torey Lovullo spoke highly of Rivera as a hitter, mentioning his “all-field approach”, per Jesse Morrison of Arizona Sports. Unfortunately, Rivera’s ability to spray the ball around the field has had its disadvantages for him. Strongly-hit balls – particularly ones in the air – have a fair greater hit probability when pulled, which Rivera doesn’t do a whole lot. Rivera has pulled 17.9% of his fly balls, which ranks in the bottom-fifth – 290th out of 354 – of qualified batters this year.
|Fly Ball Direction||Pulled||Straightaway (Center)||Opposite|
|League Average SLG%||1.740 SLG||.586 SLG||.428 SLG|
Fly balls are of course dependent only on launch angle – not exit velocity, So batted-ball events are placed into six categories based on their quality of contact (launch angle and exit velocity. The six are (in order): Barrel, Solid Contact, Flare/Burner, Poorly/Under, Poorly/Topped, Poorly/Weak. The first three listed – Barrel, Solid Contact, and Flare/Burners – are considered to be favorable types of contact, while the other three usually result in poor outcomes for hitters. A lot of the balls Rivera’s hits are favorable contact – Barrels, Solid Contact, or Flare/Burners. This year, 43.9% of Rivera’s batted-ball events are favorable contact, which ranks 50th out of the 281 batters with a minimum of 150 batted-ball events.
Unfortunately, Rivera hardly pulls the ball when he gets a good piece of it. Rivera has only pulled 28% of his batted-ball events that were classified as either a Barrel, Solid Contact, or Flare/Burner, which ranks 265th among the 296 batters with at least a total of 50 total of those three favorable types of contact. Rivera’s tendency to hit for power to the opposite field is less of a problem versus left-handed pitchers, as it’s generally easier for hitters to catch up to pitches in opposing-handedness matchups. However, Rivera’s splits are far greater than the norm.
Against lefties, Rivera has pulled 40% (12/30) of his favorable batted-ball events while only pulling 20% (9/45) versus righties.
There’s no question that Rivera could handle lefty pitching. He’d shown an easy ability to turn on pitches from lefties, which is usually easier to do in opposing-handedness matchups. There are concerns, however, if he can handle same-handedness matchups. This season has been a tale of two stories for Rivera. From his debut in late April through May, he looked like a good hitter versus righties. Since then, however, a lot of the promise he showed early on has faded.
Throughout the month of May, Rivera pulled 33% of his favorable BBEs versus righties. Since then, it’s nearly halved to 15.2%, which is the second lowest in baseball out of 121 batters in righty-on-righty matchups in that span. A part of that dip could be attributed to his swing selection – when and where he’s been swinging. Firstly, Rivera has been laying off more inside pitches versus righties. Through May, Rivera was swinging at 80% of all pitches on the inner third of the strike zone versus right-handed pitchers. Since then, he’s been only swinging barely half the time – 51.3% – on those pitches. In a larger trend, Rivera has been a lot more patient in situations where he should take advantage. Baseball Savant – MLB’s publicly available database – classifies pitch locations into four concentric zones. From the inside out, they are heart, shadow, chase, and waste. Balls thrown in the heart – the center of the zone – yield the best outcomes for hitters when contact is made. Hitters usually get those pitches when pitchers fall behind in the count and are more likely to throw in the heart of the zone.
Rivera has cooled off on capitalizing in those situations. Through May, Rivera swung at 93.3% (14 of 15) of pitches thrown in the middle (heart) of the zone versus righties. Since then, he’s swinging 73% of the time – just around the league average. Rivera’s been costing himself when he doesn’t swing the bat against RHP but also when he does swing lately.
When Rivera fell behind in the count versus righties, he whiffed increasingly more throughout the season to a massive 60-plus Swing-and-Miss% in August so far. It wasn’t all bad lately for Rivera, though. In the last month, Rivera hit three homers and only struck out at a league-average 25% K rate while he drew walks at an above-average 12.5% walk rate versus righties.
Rivera, who isn’t arbitration eligible until 2025, will earn the league minimum next year, so the D’Backs would save a whole lot if they decide to stick with him, which would allow the club to spend its resources to improve the roster elsewhere as they aim to build its next core roster. Rivera is probably the best option for the Dbacks at third base for next season as it stands. Unlike a lot of positions around the field that have begun to be filled up by the team’s top prospects, third base is a position that isn’t filled with much upper-level depth in the farm system.
Shortstop Jordan Lawlar – the fifth-best prospect in the entire league and top prospect in the organization – dominated in AA-Amarillo before getting promoted to AAA-Reno. He’ll likely debut sometime next season and could conceivably move to third base, but scouts think his arm profile suits him best in the middle infield. The closest actual third baseman in the system to the bigs is Deyvison De Los Santos – the fourth-best D’backs prospect per Pipeline – struggled overwhelmingly in 83 games in AA-Amarillo before getting transferred to the Development List on July 1st. His slash line has improved since returning to Amarillo two weeks later, but major concerns about him as a hitter still linger. This season, he’s batted to the second-worst groundball-to-flyball ratio (2.05 GB/FB) and fifth-worst swinging-strike percentage (16.8%) in the AA-Texas League among 61 qualified batters. Defensively, a lot of scouts think he profiles better at first base. He still has lots of time to develop at only 20 years old, but it’s unlikely that he’ll play a role in next year’s third-base setup even if all pans out.
In terms of external additions, this upcoming free-agent class at third base is running a little thin. Here’s a list of third basemen expected to hit free agency this offseason (I removed Justin Turner, who’ll likely exercise his $13.4 million option for ‘24).
|I. Kiner Falefa||0.3||90||28.3|
Blue Jays’ Matt Chapman will likely ink a massive contract this offseason that the Diamondbacks don’t seem likely to pursue. Jeimer Candelario is having himself a career year but could be bound for some regression back to the underwhelming results he posted beforehand. There’s a big drop in the list after those two, as the rest is filled with players nearing the end of their careers and fringe major leaguers. Rivera isn’t arbitration eligible until 2025, would cost considerably less than external options, and he’s under club control for a considerable five more years. The club could acquire a third baseman via a trade, but General Manager Mike Hazen has been reluctant to deal notable pieces of his farm system.
Mike Hazen spent a lot to acquire a trio of right-handed sluggers last offseason in Lourdes Gurriel Jr., Kyle Lewis, and Evan Longoria to move the needle, yet all three might not be on next year’s roster. Kyle Lewis has spent the majority of the year in AAA-Reno or on the injured list, only playing in a dozen games before getting called up earlier this week to replace outfielder Jake McCarthy, who was optioned to AAA-Reno. For Evan Longoria, this season could very well be the last of his storied career. Lourdes Gurriel Jr.’s MVP-winning month of May, slashing .352/.416/.714 in 23 games, made it look like Hazen acquired two players to stick here for the long haul. However, Gurriel, who’ll be a free agent this offseason, took a 180 the next two months, slashing a horrid .180/.225/.337 for a fourth-worst .244 wOBA among 173 qualified hitters in that span. He’s dug himself out of his hole at the plate, slashing .333/.391/.667 in August, although his streaky season has surely raised eyebrows in the front office if they should re-sign the six-year veteran.
Hazen’s under-the-radar addition of Rivera at the ’22 deadline might’ve been the most profitable run in the long run. Buddy Kennedy will be given a legitimate opportunity now to help right the offense, but this is not the last we’ll see Rivera. He’s had a lot of strengths this year – it’s just a matter if he can put it all together in time.
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