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Three top fantasy baseball prospects - Moises Ballesteros, Kristian Campbell, Colby Thomas - that can make big impacts. These MLB prospects are waiver wire pickups or stashes.
Stashing the right prospect at the right time can give your fantasy team a much-needed boost, especially during the second half of the regular season.
Through the opening months of the campaign, we have seen several prospects make an immediate impact in the major league. In this piece, we will look at two prospects who have had previous stints in the majors and a budding outfielder, and determine if they are worth stashing.
Should those players be left on the waiver wire, or should fantasy managers add them before their breakout? Let's dive in!
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Moises Ballesteros, C, Chicago Cubs
Current Level: AAA
Availability: 5% rostered
2025 AAA stats: 65 G, .329/.388/.494, 16 2B, 8 HR, 37 SO, 26 BB
The top backstop in the Cubs' system has already had a taste of the major leagues and is quickly approaching another promotion. During his first taste of the major leagues, Ballesteros posted a modest .188/.278/.188 slash line with just three total hits. However, during this stretch, he generated a solid .265 xBA, which suggests he was a bit unlucky.
During this stint, he also showed an elite eye at the plate, drawing walks at an 11.1% rate and striking out at a 5.6% rate.
Moisés Ballesteros forgot his shoe in the batter’s box on his way to picking up his 1st career RBI pic.twitter.com/mZG5H5iEML
— Jomboy Media (@JomboyMedia) May 16, 2025
However, given the depth of their major league roster, the Cubs opted to send Ballesteros back to Triple-A Iowa to put the final touches on his development.
Since June 1, Ballesteros has contineud ot produce at an elite level with the Iowa Cubs, boasting a .310/.370/.535 slash line with seven doubles, three home runs, 17 RBI, and a 12:8 K:BB across a 19-game stint.
During his first 44 games of the Triple-A regular season, Ballesteros posted a similar .345/.403/.492 line with nine doubles, one triple, five home runs, two stolen bases, and a 22:18 K:BB.
The 21-year-old has clearly proven he is ready for an extended look in the major leagues, but will he receive it?
Currently, the Cubs have an opening at catcher, and I am surprised that they have not given him the call. No. 2 backstop, Miguel Amaya (oblique), is on the 10-day IL and just recently began a hitting program. He has been sidelined since the end of May and likely won't return until after the All-Star break.
This has opened a spot for veteran backstop Reese McGuire to be the No. 2 option behind Carson Kelly. While the Cubs will likely want Ballesteros to remain in a starting role, which has kept him at Iowa, he has proven that he does not need any further development.
If the Cubs go on a cold streak over the next week, don't be surprised if they turn to Ballesteros to provide a spark. He could easily find a role behind the plate and split opportunities with Kelly. Given his elite production at Triple-A, a larger role in the majors could set him up for a big second half.
-Written by Andy Smith
Kristian Campbell, INF/OF, Boston Red Sox
Current Level: AAA
Availability: 5% rostered
2025 MLB stats: 67 G, .223/.319/.345 10 2B, 6 HR, 72 SO, 29 BB
Kristian Campbell was arguably the best hitter in the minor leagues last year. If he were doing now what he did last year, he'd be at the top of every stash list. However, he has spent most of this season in the majors and has struggled, so now there's a bit of stink on him.
Last season, Campbell had a 178 WRC+ across High-A, Double-A, and Triple-A. He had 20 HRs and 24 SBs while having strong plate discipline. He struck out only 19.9 percent of the time while walking 14.3 percent of the time.
He flew up prospect lists at a rapid pace and did enough to be the one member of the Red Sox "Big Three" to break camp in the big leagues.
Campbell got off to an unbelievable start to his MLB career. If you'd told me at the end of April that he'd be back in the minors and I'd be writing about him for "Prospects to Stash", I wouldn't have believed you.
He had a 151 WRC+ in March and April. However, the rookie wall hit him like a ton of bricks as he had a -8 WRC+ in May. He started to pick it up a little in June as he had a 91 WRC+. However, he wasn't hitting well enough to justify still being in the majors, as he is also not a great defender at any of the positions the Red Sox have tried him at.
As I mentioned with other demoted star prospects, this is likely just a minor reset for Campbell. This is indicative of what the Orioles did with Jackson Holliday last year. The Red Sox will likely want him to get hot for a few weeks in Triple-A before bringing him back up to Boston.
Campbell has as much upside as any player in the minors. Like I said, if he had never been in the majors, everyone would be so excited about his upcoming promotion. Don't let a rough start to his major league career let you throw him away in fantasy. If he's available, he's a solid stash in medium-deep leagues.
Kristian Campbell DESTROYS this baseball 💥
He has now reached safely in all 17 games he has played as a Major Leaguer! pic.twitter.com/cNV3yjOaBj
— MLB (@MLB) April 14, 2025
- Written by Kevin Luo
Colby Thomas, OF, Athletics
Current Level: AAA
Availability: 5% rostered
2025 AAA stats: 75 G, .296/.362/.544 21 2B, 17 HR, 91 SO, 24 BB
Thomas has been one of the most productive hitters in the minor leagues this season. The slash line sits at an impressive .299/.365/.551. This followed a 2024 season in which Thomas led the minors in extra-base hits by a wide margin, slashing .277/.342/.563 with 31 home runs and 15 stolen bases. It is time for Thomas to get a shot in Sacramento.
There is legit power in the profile, as Thomas has a 105 mph 90th percentile exit velocity. While that number is down a few ticks from last year, Thomas has topped out at 116 mph this year. His barrel rate has risen all year, now sitting at 10 percent as the ground-ball rate has trended downward.
Some of my questions about the profile have been answered. Last year, upon his promotion to Triple-A, his contact rates faltered significantly. But so far this year, Thomas has seen a seven percentage point jump in in-zone contact, and the overall contact rate is up three percentage points.
The chase rate of 34 percent is still higher than I would like to see, and I still worry about Thomas’s ability to hit good fastballs.
Right now, Thomas has a 66 percent contact rate against four-seam fastballs. The number rises against speeds of 94 mph or higher, and there are struggles against spin. It makes me very curious how Thomas will fare against MLB pitching. Against spin, Thomas has a 67 percent contact rate, which also gives me a little hesitation.
The power and speed combo is enticing, but Thomas could be a streaky hitter in the majors against better pitching.
On Monday evening, the Athletics announced they would be promoting Thomas to the major leagues. Given his power upside, he is worth adding in all 12+ team formats.
#2 A’s prospect Colby Thomas with a moonshot! 🌙💣
👀 CYCLE WATCH: ACTIVATED
Colby is a TRIPLE away from baseball history.
Let’s see if he seals it 🔥 pic.twitter.com/8DmDYGlVmh— Las Vegas Aviators (@AviatorsLV) June 3, 2025
- Written by Chris Clegg
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