Fantasy Baseball Prospect Risers - Rookies to Stash and Top Performers for Week 15 (2025)

Andy's fantasy baseball prospects sleepers and risers to know for Week 15 of 2025. He analyzes top MLB prospects and rookies to stash based on recent performances.

Welcome, RotoBallers, to my Week 15 edition of the top prospect performers. In this week's piece, we will look at two infielders who are emerging as some of the top bats at the Triple-A level. On the pitching side, we will examine a developing arm that is progressing through the minor leagues much quicker than expected.

In this weekly column, we analyze the top prospect performances of the week and determine if their performances truly matter for fantasy baseball. Should fantasy managers be stashing these prospects?

Adding the right prospect can fill the missing piece on your roster and set you up for a fantasy championship. This fantasy baseball prospects weekly series will examine a few key players in the minor leagues and assess whether they have a path to fantasy stardom in 2025.

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Carson Williams, SS, Tampa Bay Rays

Rays No. 1, Overall No. 24

The former 28th overall pick from the 2021 MLB Draft spent the entire 2024 season with Double-A and was able to receive his long-awaited first extended look at Triple-A at the start of the 2025 campaign. While he did appear in a few Triple-A games back in 2024, this season marked his first "true" look at the level.

Through his first, Williams holds a modest .212/.322/.442 line that suggests the young infielder has experienced some significant growing pains as he continues to adjust to the top pitching in the minor leagues. However, Williams has begun to hit for high power and is making a strong case to join a Tampa Bay team that is almost at the top of the AL East.

Over his last 12 contests (June 18 - July 4), the infielder has posted a remarkable .326/.463/.767 slash line with two doubles, one triple, and five long balls. On the season, Williams has gone deep 15 times. In his last four games entering Saturday, Williams has launched three of these home runs, suggesting he is beginning to find his swing.

Last season, through 115 games with Double-A Montgomery, Williams posted a .256/.352/.469 with 20 doubles, 20 home runs, and 33 stolen bases.

Is the infielder finally turning the corner at Triple-A?

While his metrics still remain a bit skewed from his rough start, Williams is showing even higher power upside than he did at Double-A. With Durham, Montgomery has generated a strong .223 ISO, which is 11 points higher than he did last summer against lesser competition. He also has posted a similar BABIP in relation to 2024, with a .296 compared to the .332 he held last season.

He has also maintained a 37.7% fly-ball rate at Triple-A, which is nearly identical to the 38.1% fly-ball rate he posted last season.

While his slow start may have taken him off the first-half fantasy radar, his recent late surge has put him back in the conversation. Currently in Tampa Bay, Taylor Walls and Jose Caballero have seen most of the time at shortstop, with Ha-Seong Kim (shoulder) missing the first few months of the campaign.

While Kim recently made his season debut, he is currently day-to-day with a calf injury and will likely see his workload closely monitored.

If the Rays remain in the Wild Card race and continue to push the Yankees for the top spot in the division, Williams should be in play to make his MLB debut in the second half.

For now, given his modest start, he should only be stashed in AL-only leagues. However, if Williams continues to show this impressive power surge is not a fluke, he will quickly enter must-stash territory shortly after the All-Star break.

Carson Williams has been one of the hottest hitters over the last month in MiLB.

He has the upside to be a premier shortstop at the MLB level with elite defense and yearly 20/20 capabilities. While there are K and whiff concerns, you cannot ignore what the 22-year-old is doing https://t.co/VKSUHGPwZg

— Inside The Diamond (@InsideTheDiamnd) June 30, 2025

Verdict: Stash in 14-team/AL-only formats

Jonathon Long, 1B/3B, Chicago Cubs

Cubs No. 13

After discussing Owen Caissie and Moises Ballesteros the previous two weeks, yet another Cub finds himself in this column. The Iowa Cubs have many emerging stars on their roster, and one who has gone under the radar this season is infielder Jonathon Long. Playing alongside Ballesteros, Caissie, Kevin Alcantara, and Matt Shaw during much of your minor league career will probably do that.

The Cubs selected Long in the ninth round of the 2023 MLB Draft, and he appears to be a steal. After appearing in 26 MiLB games following the 2023 Draft, Long received his first full taste of professional ball in 2024. He opened the campaign high High-A but needed only 68 games to prove he was ready to move up to Double-A.

With High-A, Long held a .247/.346/.417 line with 12 doubles and 10 long balls. Then, through 46 games with Double-A, the Long Beach State product continued to swing well, posting a .340/.455/.528 line with nine doubles and seven home runs.

During this stint, he also showed a remarkable eye at the plate, striking out just 33 times and drawing an impressive 35 walks.

This performance has earned him a ticket to Triple-A Iowa to open the 2025 campaign, and he has yet to slow down. Through 80 games with Iowa, Long has posted a .317/.397/.502 slash line with 11 doubles, 13 home runs, two stolen bases, and a 65:35 K:BB.

A look under the hood suggests his production with Iowa is not a fluke. Long has generated a .375 BABIP, .389 wOBA, and a 125 wRC+. The only drop in play he has seen is that his ground-ball rate has increased by four points, and his fly-ball rate has dropped two points in relation to his production at Double-A.

However, given that he is facing tougher pitching, this suggests that Long is more than ready for the major leagues.

Unfortunately, as I have discussed previously, there is no spot on the MLB roster for Long on the North Side. Michael Busch is the locked-in everyday first baseman, and while Shaw has struggled at third base, it does not seem that the Cubs would turn to another prospect regularly as we approach the second half of the season.

An MLB debut is in the cards for 2025, but adjust your expectations; it will likely be in a reserve role.

Jonathon Long enters the Top 10 1B Prospects list with Nick Kurtz graduating.

Scouting report, video and more on the #Cubs' 23-year-old with 76 hits in 67 games at Triple-A this year: https://t.co/6INnA73bCJ pic.twitter.com/GRacA7Huq8

— MLB Pipeline (@MLBPipeline) June 20, 2025

Verdict: Stash in NL-only leagues

Cam Schlittler, SP, New York Yankees

Yankees No. 10

The final player we will look at this week is right-hander Cam Schlittler. Schlittler did not appear to be in contention to make his MLB debut early this season, but he has begun to make a strong case.

The former seventh-round pick opened the season with Double-A Somerset and looked quite strong in his second stint with the club. Through 53 innings of work, Schlittler posted a 2.38 ERA and a 1.21 WHIP. During this stretch, he struck out 64 hitters while allowing only 17 walks.

This impressive start earned him a promotion to Triple-A Scranton/Wilkes-Barre. Since moving up to Triple-A, Schlittler has performed at the highest level in his minor league career.

Through his first 21 1/3 innings at the top level of the leagues, the right-hander has posted a stellar 1.69 ERA with a 0.98 WHIP. During this stretch, Schlittler has struck out 33 batters while allowing only eight free passes. In his last two outings in June (June 19 and June 25), Schlittler has struck out at least nine batters in each game and allowed only two total walks.

Unfortunately, the right-hander took a slight step back in his first start in July when he allowed seven hits and six runs.

However, unlike the other names on this list, Schlittler has a clear path to the big leagues. Currently, Marcus Stroman occupies the No. 5 spot on this list but has not been remarkably consistent. Luis Gil (lat) is nearing a rehab assignment and could even take this spot, but will likely be on a strict innings limit.

On Saturday afternoon, following the news that Clarke Schmidt (forearm) will undergo Tommy John surgery, the Yankees announced that they will be promoting Schlittler to the major leagues.

While he may not be given a long leash, given his elite production at Triple-A, he is worth adding in all 12+ team leagues this weekend.

Cam Schlittler (NYY) was dominant today as he struck out 9 over 6 scoreless innings

The stuff is bonkers! pic.twitter.com/jbrO0dHhwG

— Thomas Nestico (@TJStats) June 26, 2025

Verdict: Add in all 12+ team leagues

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