Buy Low, Sell High Fantasy Baseball Trade Advice for Week 15 (2025)

Joey's fantasy baseball buy low, sell high trade advice for Week 15 of 2025. His undervalued fantasy baseball trade targets and overvalued players to trade away.

Welcome, RotoBallers, to our weekly buy/sell article highlighting the best players to trade for and trade away. Every week of the fantasy season, we will determine which players fantasy managers should be buying and selling. Now is the perfect time to offer your league mates some trades, especially since we are approaching the All-Star break. 

In this week's edition, we will look at five players to buy and sell. The three players fantasy managers should be buying haven't contributed much in recent weeks, but that should change soon. The two sell-high options are currently overperforming and are set for some regression in the next few weeks. 

So, which players should fantasy managers buy and sell for Week 15 of the fantasy baseball season? Let's dive in and find out. 

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Undervalued Fantasy Baseball Players to Trade For

Marcell Ozuna, DH, Atlanta Braves

Atlanta Braves designated hitter Marcell Ozuna found himself going early in 2025 fantasy baseball drafts. After hitting .302 with 39 home runs and 104 RBI across 162 games last year, it made sense why most fantasy managers wanted to select him in drafts. However, Ozuna has been somewhat of a disappointing fantasy option in 2025.

He is currently batting .238 with 11 home runs and 40 RBI in 85 games. Those numbers are unlike the slugger, considering he is only on pace for 20 home runs and 73 RBI this year. Ozuna is being more selective at the plate in 2025, which could be contributing to his subpar power numbers. The veteran has a 58.1% zone swing rate. For comparison, he had a 72.5% zone swing rate last season.

Marcell Ozuna unties it with a three-run shot 💪 pic.twitter.com/dUclAoWvuH

— MLB (@MLB) June 14, 2025

Despite his early-season struggles, the Braves designated hitter is the perfect buy-low candidate. He is still hitting the ball hard, and his expected slugging (.479) is 99 points higher than his actual slugging (.380). With a 10.9% barrel rate and a 91.4 mph average exit velocity, we could see Ozuna turn it up in the second half.

That was surely the case during the 2024 season. Ozuna hit .302 with 10 home runs in July and batted .327 with six home runs in August of last year. As a result, fantasy managers should be looking to acquire him before the All-Star break. He is still one of the best power hitters in the game.

Jesus Luzardo, SP, Philadelphia Phillies

Philadelphia Phillies starting pitcher Jesus Luzardo has had too many rough outings this season. He allowed 12 runs across 3 1/3 innings against the Milwaukee Brewers on May 31, gave up eight runs across 2 1/3 innings against the Toronto Blue Jays on June 5, and recently allowed six runs (five earned runs) in two innings pitched against the Cincinnati Reds on July 4.

Those outings collectively are a large reason why Luzardo has a 4.44 ERA through 18 starts. While it's hard to ignore those three outings, the southpaw has pitched well in most of his other starts this season. If you exclude those three outings above, the 27-year-old has a 2.31 ERA across his 15 other starts in 2025.

The Jesus Luzardo Experience pic.twitter.com/J4aewb8Fsw

— Jon Anderson (@JonPgh) July 5, 2025

Yes, the lows are really low for Luzardo. Not many pitchers of his caliber have had three outings like that in 2025. But when he's at the top of his game, he is one of the most dominant left-handers in the majors. Therefore, fantasy managers should be looking to trade for the Phillies pitcher in Week 15.

He has a solid 30.6% chase rate, a 30.7% whiff rate, and a 27.2% strikeout rate this year, and it might be fairly easy to trade for him. Given that his expected ERA (3.65) is 79 points lower than his actual ERA (4.44), some better outings could be ahead for the southpaw.

Hunter Greene, SP, Cincinnati Reds

This might be your last chance to buy low on Cincinnati Reds starting pitcher Hunter Greene. The flame-throwing right-hander has been out for over a month due to an ongoing groin injury. Greene originally landed on the 15-day IL on June 4, but he should return very soon. Although he suffered a setback on Monday, the 25-year-old is still a great buy-low candidate. 

So, see what it would take to acquire Greene while he is still rehabbing from his groin injury. The Reds pitcher had a 2.72 ERA and 73 strikeouts in his first 11 starts this season, and he allowed two runs or fewer in nine of those 11 outings. We should expect the 2024 All-Star to return to that level of dominance once he is back from the IL.

Greene ranked in the 82nd percentile or better in expected ERA (2.92), expected batting average against (.208), chase rate (32.8%), strikeout rate (30.8%), and walk rate (5.9%) to start the year. Those metrics should help the right-hander finish with all-around strong numbers in 2025. That makes him one of the best pitchers to trade for right now.

Overvalued Fantasy Baseball Players to Trade Away

Lucas Giolito, SP, Boston Red Sox

After missing the entire 2024 season due to elbow surgery, Boston Red Sox starting pitcher Lucas Giolito is back better than ever. He has a 3.66 ERA and 58 strikeouts across 66 1/3 innings pitched this year. More importantly, Giolito has looked untouchable on the mound in recent weeks. He has thrown five straight quality starts dating back to June 10.

The veteran has been on an unreal stretch over the past month. He has allowed two runs or fewer in five consecutive outings and has a 0.83 ERA in those five starts. Giolito's best outing during this span came back on June 16 when he tossed six shutout innings with 10 strikeouts against the Seattle Mariners.

Lucas Giolito's past 5 starts 😳:

32.2 IP
0.83 ERA
31 K pic.twitter.com/zGX0ggu7h3

— MLB (@MLB) July 4, 2025

Although Giolito appears to be in a groove on the mound, it might be time to sell him high in Week 15 of the fantasy baseball season. He is pitching way better than his metrics suggest, and some regression should be coming his way in the next few weeks. For starters, his ERA (3.66) is 113 points lower than his expected ERA (4.79). 

On top of that, Giolito ranks in the 30th percentile or worse in expected batting average against (.287), average exit velocity (90.5 mph), whiff rate (21.1%), and hard-hit rate (43.9%). So, now might be the best time to trade away the Red Sox pitcher. His fantasy value might never be higher. 

Jo Adell, OF, Los Angeles Angels

Los Angeles Angels outfielder Jo Adell has been on an absolute tear at the plate over the past few weeks. He is batting .361 with six home runs, 16 RBI, and 12 runs scored across his last 17 games. We are finally starting to see why Adell was one of the most touted prospects in all of baseball a few years ago. He ranked No. 6 overall on MLB Pipeline's prospect rankings entering the 2020 season. 

However, Adell failed to showcase his potential in his first five major league seasons from 2020 to 2024. The former first-round pick slashed .211/.268/.381 with 38 home runs, 128 RBI, and 28 stolen bases in his first 308 games heading into 2025. Now, the 26-year-old looks like a completely different player at the plate. 

He is making strong contact, and his 77.5 mph bat speed currently ranks in the 99th percentile. While there is a lot to be encouraged by from Adell, the Angels outfielder is one of the bigger sells in fantasy at this point in the season. 

His high chase rate (32.1%), whiff rate (29%), and strikeout rate (23.5%) are all concerning signs moving forward. Adell also ranks in the bottom half of the league in squared-up rate (20%) through the first few months. These metrics could cause his numbers to decline in the coming weeks, and a major slump is almost inevitable with a high whiff rate.  

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