Each week in this column, we will continue to look at players through the lens of advanced metrics and various statistical trends to discover which players are underachieving or overachieving in the hopes of identifying potential trade targets or those worth selling at peak value.
Some of the data can be used to acquire a player at a lower price point because he has lost value or sell players when they peak in value for a larger return on your investment.
Find stats showing that a player’s value is actually on the upswing and acquire that player at a fair price, knowing his value is almost sure to keep increasing anyway. Conversely, sell players who hold widely held perceived value but for whom underlying stats show may be on the verge of seeing the floor collapse and get out now.
Thus far, the data sample is starting to stabilize, and while more time is still needed to truly gather which players look like premium buys or sunk costs, we have enough to guide our decisions.
Remember, every ball hit and thrown still tells a story, and if you want to review previous Buy Low, Sell High suggestions from prior weeks, you can view them here.
View your league’s top available players with My Playbook 
Buy Low
Pete Alonso (1B – NYM)
Pete Alonso is not having a poor season, but no one expected to see the likes of Brandon Crawford and Adolis Garcia sitting with more home runs than Alonso in the middle of June. Yet, here we are with Alonso sitting at just 11 home runs so far. Many of the names above him on the home run leaderboard are unlikely to keep up their torrid pace, but there are many reasons to believe Alonso has a power surge in store. First, Alonso’s 10.3 Brls/PA% ranks as the 10th highest in baseball. Moreover, his 47% HardHit% is the highest of his career so far, and his 92.6 MPH Average Exit Velo is also a top mark for him as well. Best of all, Alonso is striking out less than he did over his first two seasons as well.
Pete Alonso reached 80 career home runs in 274 games, the 3rd-fewest games to 80 HR, behind only:
Ryan Howard: 245 games
Aaron Judge: 264 games— Sarah Langs (@SlangsOnSports) June 20, 2021
Adam Duvall (OF – MIA)
Adam Duvall might be one of the better streamable bats in baseball, but there is a good argument for acquiring him for the long haul this season. Duvall’s 9.6 Brls/PA% ranks as the 13th best in baseball, and his 113.8 MPH Max EV is good for a top 35 slot in the league. It doesn’t hurt that Duvall’s 49% HardHit% is top-25 in baseball as well. He’s leading the NL in RBIs with swings like this:
ADAM DUVALL HAS DRIVEN IN SIX RUNS ON TWO DAMN SWINGS pic.twitter.com/2c5ydplLeo
— Jared Carrabis (@Jared_Carrabis) June 19, 2021
Alec Bohm (3B – PHI)
Alec Bohm has largely been a disappointment for anyone who hoped he would hit better than .233, but hey, baseball is hard, right? Look, Bohm has struggled to adjust – do doubt – but his 50.3% HardHit% is actually top-20 in all of baseball, and his 92.6 Average Exit Velo slots in as the 13th best in baseball. Bohm’s .410 BABIP last year in 44 games inflated expectations heading into this year, but underlying stats show a hitter who is much better than surface stats would suggest.
How did Joe Girardi finally get Alec Bohm past his early season struggles?
Nothing but patience: @Phillies | #RingTheBell pic.twitter.com/IP5YRopB8y
— MLB Network Radio on SiriusXM (@MLBNetworkRadio) June 21, 2021
Patrick Sandoval (SP – LAA)
It’s only been a few starts, but Patrick Sandoval is in a groove. He currently sits in the 94th percentile in Whiff%, which is not surprising given how deep his repertoire is, and he’s posting a GB% over 53%. Sandoval has long been the kind of starter you hope can shore up the back end of your fantasy rotation, and now he’s pitching like it. The 3.69 ERA and 1.26 WHIP look solid, but underneath the hood, Statcast paints a mostly pedestrian pitcher, minus a high spin rate on the curve. Use that to your advantage if Sandoval’s manager picked him up to stream and figures to hold him. Sandoval’s xFIP sits at 3.73, and his SIERA checks in at 3.90, so the success is mostly earned.
Luis Castillo (SP – CIN)
There are very few pitchers who have been more frustrating to own this season than Castillo. Castillo might be sporting a 5.61 ERA, but the xERA sits at 3.99. Moreover, his xwOBA comes in at 3.14, and hitters should be slugging .378, not .424 off him. Castillo has pitched at least six innings in three of his last four starts, and he’s posted at least seven strikeouts in his last three starts. He has also allowed three runs or less in five consecutive starts. As the weather warms, so too does Castillo.
Sell High
Marcus Stroman (SP – NYM)
Stroman has always been a solid points-league starter due to his ability to soak up innings. He’s having a remarkable season thus far, especially when you look at his 2.35 ERA. Sadly, pull back the curtain, and you will find a 4.28 xERA, marking one of the largest differentials in baseball among starters. Stroman’s 7.97 K/9 doesn’t do much, and that is actually the highest rate of his career.
Walker Buehler (SP – LAD)
In general, I always advocate for selling high on pitchers. They tend to break easily, usually without warning. Buehler is 7-0 with a sterling 2.38 ERA, 0.90 WHIP, and fresh off a nearly eight IP with 11 Ks and just two hits allowed to the Arizona Diamondbacks. His value may not get any higher. Buehler’s xERA (3.57) suggests some regression is in order. He will continue to be very good, but Buehler’s K/9 (8.74) is actually the lowest of his young career, while the 86.2% LOB% is the highest. If you can fetch a premium return, selling now has its merits.
Matt Olson (1B – OAK)
Matt Olson is having a stellar year, but he’s playing a bit over his head. He’s hitting over .300 with 20 bombs, but xBA says he should be hitting .282. A deeper look at his metrics reveals a much different player than Olson has ever been. Perhaps the biggest change has been reducing his K-rate to 16.1%. Olson has never posted a K% below 24% at the big league level. It’s fair to question whether that will hold. Selling now is a bet that he won’t be quite as selective going forward.
Steven Duggar (OF – SFG)
Steven Duggar is a defensive phenom who appears to be blossoming as a hitter, putting together a BA over .300 with a nice blend of power and speed (six HRs, four SBs). Sadly, the xBA is only .242, and the .403 wOBA is masking a .338 xwOBA. That’s the largest differential in baseball right now. He’s the perfect sweetener to add to a deal for a premium asset.
Create MLB DFS lineups with our Lineup Optimizer Tool
Subscribe: Apple Podcasts | Spotify | Google Podcasts | Stitcher | SoundCloud | iHeartRadio
If you want to dive deeper into fantasy baseball, be sure to check out our award-winning slate of Fantasy Baseball Tools as you navigate your season. From our Lineup Assistant – which provides your optimal lineup based on accurate consensus projections – to our Waiver Wire Assistant – that allows you to quickly see which available players will improve your team and by how much – we’ve got you covered this fantasy baseball season.
Paul Ghiglieri is a featured writer at FantasyPros. For more from Paul, check out his archive and follow him @FantasyEvolves.
