Fantasy Baseball Buys/Sells - Using Expected Statistics to Find Regression Targets

April 26, 2023

Kev Mahserejian (@RotoSurgeon) takes a look at fantasy baseball buy/sell trade targets - early regression candidates and whether they will improve or decline.

Using expected offensive statistics such as xBA, xwOBA, and xSLG, we can locate some hitters who could be heading for major regression (positive or negative). Statcast is not a perfect science as there are nuances to batted balls that don't account for human abilities and or limitations. xBA is typically lower for speedsters who can dink singles and on the flip side higher for hard-hitters who are slow.

Not to say it all must be taken with a grain of salt but there is certainly reason for pause on particular players. Statcast is a fantastic tool that helps fantasy managers see the true abilities of players but is better utilized later in the season when more batted ball data is available.

For now, Kev Mahserejian (@RotoSurgeon) takes a look at early regression candidates and what measures to take in fantasy with them moving forward.

Positive Regression - Fantasy Baseball Buys

MJ Melendez, Kansas City Royals

Actual Stats: .156 AVG / .266 SLG
Expected Stats: .226 AVG / .504 SLG

Melendez has factors beyond luck working against him such as a 33.8% strikeout rate, however, when he does make contact, it is loud and worthy of buying. 74 PA is still an extremely small sample to determine that he will sit above 30%+ strikeouts all season as he has not dealt with such issues since his early minor league days of 2019.

The Royals continue to bat Melendez within the top of the order and he is still taking walks at a high 12% clip. The BABIP will naturally adjust from .231 to at least .250 as it was last season. From there, he will get the ball over the fence in the coming as the weather warms up and luck shifts back his way.

Josh Naylor, Cleveland Guardians

Actual Stats: .153 AVG / .254 SLG
Expected Stats: .260 AVG / .479 SLG

Naylor is far from worth giving up on. The dual-eligible power/RBI threat is a sleeping giant in a talented offense that has seen other studs like Jose Ramirez and Josh Bell struggle to start this season. Naylor is starting against LHP occasionally as well, putting aside any doubt as to whether the team believes in him. While Naylor is better utilized as a platoon bat in fantasy, his presence is no doubt an impact as he had 20 HR, 79 RBI, 6 SB, and a .256 avg in 2022 fresh off ankle surgery the season prior.

Alek Thomas, Arizona Diamondbacks

Actual Stats: .200 AVG / .345 SLG
Expected Stats: .312 AVG / .496 SLG

Thomas regularly bats toward the bottom of the order for Arizona but that may not be for long. Thomas is far and away making the best contact of any Diamondbacks hitter to start this season and it is only a matter of time before regression comes to fruition. Thomas is unlikely to crack a .300 average or 20 HR due to his groundball-heavy prowess but there is a viable fantasy bat in here even without the speed that's possessed.

Thomas has the benefit of playing the OF at a near-elite level to keep him in the lineup through slumps. It is so good that he even manages to face LHP despite a .420 OPS against them since 2022.

Miguel Vargas, Los Angeles Dodgers

Actual Stats: .216 AVG / .314 SLG
Expected Stats: .278 AVG / .434 SLG

Miguel Vargas suffered a thumb injury during Spring Training that limited him but not enough to delay his start to the season. The 23-year-old second baseman had been deemed a potential Rookie of the Year candidate as expectations mounted after Gavin Lux's unfortunate injury and that upside is still possible! Unfortunately, his own teammate James Outman is leading the race at the moment while he underperforms expected numbers by a significant margin.

Vargas's xwOBA is 45th in the MLB while his actual wOBA is a slightly above-average 113th. That gap should close in the coming weeks as the Dodgers' offense naturally figures itself out.

Negative Regression - Fantasy Baseball Sells

Chas McCormick, Houston Astros

Actual Stats: .275 AVG / .500 SLG
Expected Stats: .193 AVG / .302 SLG

McCormick is a complete fugazi with numbers this bad. While the jump in steals is a fantastic boost to his fantasy value, the regression monster is looming. Also, McCormick is currently on the IL due to a back issue and may be limited physically upon return as a result. If rostered, a grace period of a week or so is fair to see if his early-season luck continues but more than likely he's universally dropped come May.

Jazz Chisholm Jr., Miami Marlins

Actual Stats: .213 AVG / .412 SLG
Expected Stats: .187 AVG / .343 SLG

Chisholm's fall from grace is disappointing. The general fantasy value for Chisholm is still positive due to 3 home runs and 6 stolen bases but a 39% K is eye-popping, to say the least. His other surface numbers aren't even impressive enough to worry about any negative regression that may come his way later. 2023's MLB the Show cover athlete was a budding superstar last season prior to a season-ending back injury but now one must wonder whether that injury is either limiting his body or causing him to play scared.

Hunter Renfroe, Los Angeles Angels

Actual Stats: .263 AVG / .487 SLG
Expected Stats: .221 AVG / .382 SLG

Hunter Renfroe has more power in his bat than his Statcast numbers suggest given his history of previously strong data but this start to the season is certainly something to keep an eye on. Renfroe has always been a streaky hitter and maybe lucked into a few home runs thus far. However, he is always good for a hot month or two where the ball is absolutely smoked making this regression candidate forgivable.

Bryson Stott, Philadelphia Phillies

Actual Stats: .360 AVG / .472 SLG
Expected Stats: .273 AVG / .364 SLG

Bryson Stott is not tough to make a case against given that he is not producing monster fantasy numbers outside of his average. His hit streak to start the season is fun but does very little for fantasy managers outside of points leagues. While Stott can continue to outperform his expected average and end up on the fringe of .300, it will not matter if the runs, HR, or RBi are not present. He can be dropped at the first sign of struggle.

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