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Five fantasy baseball waiver wire pickups, sleepers, and trade targets for Week 13 -- undervalued hitters outperforming their rostership and should be more widely owned.
As Week 13 of the fantasy baseball season gets underway, the waiver wire remains a goldmine for savvy managers looking to gain an edge. Whether you're dealing with injuries, slumps, or simply looking to upgrade, now’s the time to pounce on undervalued hitters who are flying under the radar in many leagues.
This week’s list features five such players — Alec Burleson, Colton Cowser, Javier Baez, Trevor Story, and Jo Adell — all of whom are underowned but offer the potential to contribute across multiple categories.
From hot bats to returning veterans, these waiver wire targets could be key difference-makers as the season enters its second half.
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Alec Burleson, 1B/OF, St. Louis Cardinals
55% rostered
In his four seasons on the Cardinals, Burleson has been a reasonably consistent, underrated hitter. He made his MLB debut in September 2022, carrying over his rookie status into the 2023 campaign. Since then, Burleson has accrued 1.6 bWAR and slashed .270/.316/.423 with 51 doubles, 38 home runs, and 146 RBI.
The 26-year-old continues to be undervalued, as he's rostered at just over 50 percent while sporting a .126 OPS+, .127 wRC+, and .353 wOBA on the year. Burleson has especially been hot lately, mashing four homers and collecting 11 RBI in his last seven games, striking out just three times.
Alec Burleson makes it a 4-run 5th inning for the @Cardinals! pic.twitter.com/PGpcECJIMr
— MLB (@MLB) June 24, 2025
That trend isn't new to Burleson -- he doesn't strike out often, with 33 in 249 PA this season. That places him in the 89th and 91st percentiles, respectively, in Whiff% and K%. The left-handed hitter also boasts a .282 xBA, alongside an average exit velocity of 91.6, which represents an improvement from last season, when he averaged 89.7.
He's played a key role in helping St. Louis to an 8-2 record in their previous 10 games and a 44-36 record overall. The Cards are 2.5 games back of the first-place Chicago Cubs, keeping them firmly in the NL Central race.
Colton Cowser, OF, Baltimore Orioles
50% rostered
It's been a season to forget for the Orioles. While there are plenty of reasons why this year has been a wash in Baltimore, being without Cowser until June 2 was one of them. Cowser began the year on the injured list due to a left thumb fracture. Since his activation, the 25-year-old has provided a bit of an offensive spark for the struggling club.
Colton Cowser has started 12 games since returning from the injured list.
He’s homered in five of them.
He’s slugging .622 with a .914 OPS since he came back. pic.twitter.com/XSCpoel4Mo
— Jacob Calvin Meyer (@jcalvinmeyer) June 20, 2025
He's slugging .481 with three doubles and six homers in 85 plate appearances. Cowser's six home runs are already half of the team's leader, Cedric Mullins, in 174 fewer PAs. Two months of Cowser likely wouldn't have salvaged the Orioles' season, but one wonders how many homers he could've had by now, and if he could've helped the team to more wins with his bat.
At 34-46, Baltimore is in the basement of the AL East with a 0.2% chance of making the postseason, per Baseball Reference.
Javier Baez, 3B/SS/OF, Detroit Tigers
43% rostered
It's been a bounce-back year for Baez. After signing with the Tigers in December 2021, it's been a downward spiral for Baez offensively. From 2022 to 2024, the 32-year-old produced a .610 OPS and 71 OPS+, and was worth -0.7 fWAR last season. It was a far cry from Baez's days with the Cubs, when he was a two-time All-Star, Silver Slugger, and Gold Glove Award winner, and NLCS MVP.
However, the former first-round pick finally appears to be himself again in 2025.
That sweet Javier Báez swing 😮💨 pic.twitter.com/hvb2HV6bEd
— MLB (@MLB) June 18, 2025
Baez has slashed .289/.329/.469 posted a 125 wRC+, tallied 22 extra-base hits, and added 36 RBI in 243 PA. He's been on fire recently, too, slugging .762 and reaching base at a .440 clip, notching eight hits, including two home runs, in his last seven games.
Not to mention, he's been extremely clutch -- batting .321 with three homers and 29 RBI with runners in scoring position. Baez's resurgence has helped the Tigers to the best record (50-31) in the majors. Detroit is a force to be reckoned with, Baez, Tarik Skubal, Riley Greene, Spencer Torkelson, and Gleyber Torres leading the way.
Perhaps it's Baez's recent track record that's making fantasy managers hesitant to roster him. He also still strikes out a decent amount, and walks are few and far between. Baez averages an 88.1 mph exit velocity, and his xBA of .253 and xSLG of .404 aren't encouraging. While the underlying numbers don't support his recent success, he's still been consistently productive and looks much better than in previous seasons.
Trevor Story, SS, Boston Red Sox
33% rostered
It's been a roller coaster of a first half for Story. The former All-Star looked cooked in May, batting .158 with 35 strikeouts in 95 at-bats. However, he's been able to pick it up a bit in June, with four homers and 18 RBI across 22 games this month. Still, the two-time Silver Slugger is certainly not what he used to be.
TREVOR STORY TIES IT!
Cool moment after what happened last year in Anaheim… pic.twitter.com/D0BrmxoRi8
— Tyler Milliken (@tylermilliken_) June 24, 2025
We examined Story's performance in Week 11 and determined that any offensive success he's currently experiencing is likely unsustainable in the long run unless significant changes are made to his game. He's looked lost at the plate for most of the year, so a couple of home runs here and there don't mean he's magically fixed or back to who he was during his time in Colorado.
Advanced metrics also confirm this. It's reasonable to take a chance on him while he's hot, but it's understandable why he's only rostered in about 30 percent of leagues. For most teams, Story probably isn't worth the roster spot. If you're in a league with sparse options on the waiver wire, however, he could be worth the risk right now.
He's homering, which is worth something, but if you can't afford the strikeouts, it might be better to pass on him.
Jo Adell, OF, Los Angeles Angels
34% rostered
The Angels' problem isn't that they lack talent; they have it. The issue is that none of their players is consistent offensively. Adell is one of those players -- as well as Taylor Ward and Luis Rengifo. Each player seemingly goes through a period every season where they look unstoppable, but they can't sustain that through a 162-game campaign.
The 26-year-old has 17 homers in 2025, which is tied for third on the team, and his 41 RBI place second. Adell has 10 home runs just this month, alongside a 1.014 OPS. The former first-round pick boasts tremendous bat speed, which enables him to barrel the ball at a 14.6% rate, with an xSLG of .545 and an xwOBA of .376. He's also posted a 116 wRC+ and a .337 wOBA.
Jo Adell now has 9 home runs in his last 18 games 😳 pic.twitter.com/Dr8qv84zmb
— MLB (@MLB) June 19, 2025
He doesn't hit for average and instead hits for power, with a career .215 BA entering his sixth season. Still, his .676 career OPS leaves much to be desired as well. In other words, there hasn't been a season where Adell has put it all together.
That said, he has dealt with a plethora of injuries that have likely hindered his progress and prevented him from reaching his full potential during his major league career. Of course, the Angels will take the home runs, as Adell is well on his way to setting a new career high in the category.
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