Fantasy Baseball Trade Targets - Buy/Sell for Week 9 (2025)

Fantasy baseball trade candidates to buy/sell for Week 9 (2025). Joey's fantasy baseball undervalued players to target in trades, and overvalued to trade away.

It's crazy that we are already two months into the fantasy baseball season. It has been a wild start to the year, and things will only get tougher for fantasy managers as we head into the summer months. Therefore, now is the perfect time to start making some trades in your fantasy leagues. 

In this article, we will look at five players fantasy managers should be buying/selling heading into Week 9. The buy-low options are players who haven't necessarily been strong fantasy options in quite some time. The sell-high options are players due for some regression in the coming weeks. 

So, which players should we buy and sell for Week 9 of the 2025 fantasy baseball season? Let's dive in and find out. 

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Undervalued Fantasy Baseball Players to Trade For

Wilyer Abreu, OF, Boston Red Sox

Boston Red Sox outfielder Wilyer Abreu got off to a strong start at the plate. The 25-year-old hit .295 with six home runs, six doubles, 21 RBI, and four stolen bases in his first 30 games this season. However, Abreu has gone into a bit of a slump in recent weeks, hitting just .208 with 12 strikeouts across 19 games in May.

This rough stretch has made some fantasy managers impatient with the Red Sox outfielder. If someone in your league is looking to sell him, see what it would take to acquire him. Better offensive days are ahead for Abreu, and there are some things to be encouraged by during this slump. Although he has just 15 hits over his last 72 at-bats, five of those hits went for home runs.

Wilyer Abreu has 11 HR in his first 41 games of the season. He's 25 years old.

The full list of @RedSox to do that, at his age or younger, to begin a season... pic.twitter.com/L5WRxdAI1F

— Mike Monaco (@MikeMonaco_) May 13, 2025

With a .573 expected slugging, 91.7 average exit velocity, 14% barrel rate, and 18.3% whiff rate this season, Abreu's bat should heat up again very soon. That makes him the perfect buy-low target heading into Week 9 of the fantasy baseball season. 

His metrics suggest that his recent slump won't last much longer, and he already has 11 home runs on the season. It's very possible that Abreu hits 25 home runs and steals double-digit bases in 2025. 

Jazz Chisholm Jr., 3B/OF, New York Yankees

It has been a while since we have seen New York Yankees infielder Jazz Chisholm appear in a major league game. Chisholm injured his oblique back on April 29, and an MRI revealed a high-grade strain a few weeks ago. His initial timeline for a return was around four to six weeks, meaning we could see the former All-Star back at some point in June. 

As a result, the 27-year-old is a great buy-low candidate right now. He continues to progress in his recovery and has been hitting off a tee for the past week. Given it has been a little over three weeks since Chisholm suffered that oblique strain, his return could occur within the next few weeks. Once he is eventually activated, he will be a strong all-around fantasy contributor. 

It was just last season that Chisholm hit .273 with 11 home runs and 18 stolen bases in 46 games with the Yankees. Even though the Yankees' utility specialist hit just .181 in his first 30 games this season, it's hard to ignore his home run and stolen base potential. He hit seven homers and stole six bases before his injury.

So, you're getting a player who could potentially hit 20 home runs and steal over 40 bases. Chisholm reached both of those marks in 2024, and there's a strong chance that he will hit over 20 home runs for the second consecutive year. His 14.9% barrel rate currently ranks in the 87th percentile to start the season. 

Brent Rooker, OF/DH, Athletics 

Athletics outfielder Brent Rooker has emerged as one of the best power hitters in the game. He hit 30 long balls in 2023 and followed that up by hitting 39 home runs last year. After hitting .293 at the plate with 39 home runs, 112 RBI, and 11 stolen bases in 2024, Rooker was a popular pick early in fantasy drafts. 

However, the 2023 All-Star has struggled a bit offensively in May. He entered Thursday's contest with a .197 batting average and just two home runs across his first 19 games in May. During this stretch, he has just four multi-hit games while striking out 23.6% of the time. 

Despite those recent numbers, Rooker is the perfect buy in most fantasy leagues. We are starting to see signs of life from him at the plate following a 3-for-4 day with one home run and two RBI in Thursday's loss against the Angels. His metrics also suggest that things should eventually even out for the 30-year-old. 

Brent Rooker hits this baseball off the building in left field 😳 pic.twitter.com/PbL6x1FpQw

— MLB (@MLB) May 22, 2025

Rooker has a .372 xwOBA, a .276 expected batting average, a .531 expected slugging, and a 13% barrel rate. Given that he plays half of his games at a minor league ballpark (Sutter Health Park), another 30-home run season is surely attainable for the slugging outfielder.

Overvalued Fantasy Baseball Players to Trade Away

Gavin Williams, SP, Cleveland Guardians

Fantasy managers started to notice Cleveland Guardians pitcher Gavin Williams during the spring. He allowed just four runs across 17 1/3 innings pitched in spring training to go with 26 strikeouts and just four walks. Williams, though, was the opposite of that pitcher to begin the regular season. 

He had a 5.14 ERA, 14 walks, and 28 strikeouts in his first six starts in 2025. Some of those outings included allowing five earned runs with four walks across six 1/3 innings against the Baltimore Orioles on April 16 and giving up four runs on seven hits with two walks across just two innings against the Minnesota Twins on April 28. 

However, Williams has been a much more efficient pitcher in recent outings. He has a 2.25 ERA and 29 strikeouts over his last four starts and just tossed six innings of one-run ball with six strikeouts against the Twins on Wednesday. The re-emergence of his cutter has been a large reason why the Guardians pitcher has found some success on the mound as of late. 

🚨Gavin Williams is throwing Cutters as his #2 pitch. 🚨

THIS IS NOT A DRILL pic.twitter.com/OZ9zxuFz3B

— Nick Pollack (@PitcherList) May 21, 2025

While some fantasy managers might believe that Williams' recent numbers are here to stay, it's best to trade away the right-hander before his next start. He's allowing a ton of hard contact this season while walking batters at an extremely high rate. The 25-year-old has walked multiple batters in eight of his 10 starts and currently carries a 12.4% walk rate. 

As a result, he likely won't be able to maintain a low ERA for most of the season.

Will Warren, SP, New York Yankees

It really is impressive what New York Yankees starting pitcher Will Warren has done on the mound in recent weeks. He tossed seven 1/3 innings of one-run ball with seven strikeouts against the Athletics on May 9, threw five innings of two-run ball with nine strikeouts against the Mariners on May 14, and five 2/3 scoreless innings with 10 strikeouts against the Rangers in his most recent start on Tuesday. 

During this three-game stretch, Warren has allowed just three earned runs while striking out a whopping 26 batters. However, this is a fantastic opportunity to sell the right-hander.

He has three tougher matchups upcoming against the Rockies (at Coors Field), Dodgers, and Red Sox, and his metrics suggest that he could be hit harder in these outings. Warren ranks in the 25th percentile or worse in chase rate (24.6%), average exit velocity (91.9 mph), hard-hit rate (50%), and barrel rate (10.7%) in the early going. 

While there is potential for Warren to be a consistent fantasy option, selling him high might be the best move. Only two of his pitches (four-seam fastball and changeup) have limited hitters to under a .210 batting average this season, and he could have less success on his changeup in the coming weeks. Opposing hitters have an expected .318 batting average against the pitch this season. 

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