MLB Prospect Debuts: Fantasy Baseball Waiver Wire Pickups and Rookie Stashes (Week 6)

May 6, 2026

Marty's fantasy baseball prospect stashes, sleepers, and rookie waiver wire pickups for Week 6 of 2026 -- recent MLB prospect debuts and potential call-ups to monitor.

Use this article as a guide to stay ahead of the curve. This week, we’ll look at two pitchers off to strong starts in the majors, along with two recently promoted hitters. Before scanning your waiver wire, take a moment to evaluate which players, both in real life and on your roster, are underperforming. If you see an opportunity to upgrade, don’t hesitate to take a chance, especially in shallower leagues.

This column highlights players rostered in fewer than 60% of Yahoo! leagues. If you have any questions or comments, feel free to reach out on X @Marty_Tallman. Now, let’s dive into this week’s promising prospects!

Fantasy Baseball Hitter Prospects To Target

Braden Montgomery, OF, Chicago White Sox (2% rostered)

Level: Triple-A

2026 Stats: 126 PA, .313/.429/.606, 20 R, 6 HR, 22 RBI, 2 SB, 16.7% BB%, 25.4% K%, 162 wRC+

The Chicago White Sox have been playing better than expected, but their current outfield has struggled at the plate and may soon need reinforcements from the minors. Over the past two weeks, White Sox outfielders have produced an 84 wRC+, ranking sixth-worst in baseball over that span. At the major league level, the group currently includes Andrew Benintendi, Sam Antonacci, Tristan Peters, Jarred Kelenic, and recently signed veteran Randal Grichuk.

Is Braden Montgomery the answer to their problems? He definitely could be. The White Sox’s No. 5 prospect is a switch-hitting power bat with loud tools, and he was just promoted to Triple-A. Across three levels last season, Montgomery slashed .270/.360/.444 with 12 home runs and 14 stolen bases while posting a 25% strikeout rate and an 11% walk rate in 517 plate appearances.

Coming into the season, Montgomery was not expected to be a quick call-up, but of his 30 total hits in Double-A this year, 14 have gone for extra bases, leading to a .305 ISO and a .621 slugging percentage. The 23-year-old hits the ball hard while walking nearly 17% of the time. While his biggest flaw is a lot of swing-and-miss in his profile, that's normal given his approach.

Major League hurler? No problem for Braden Montgomery!,

The @whitesox No. 1 prospect cracks his 5th roundtripper for the Double-A @BhamBarons, this one off rehabbing big leaguer Caleb Ferguson. pic.twitter.com/jGJO4cQ9l5

— MLB Pipeline (@MLBPipeline) May 1, 2026

If he continues to hit and maintains his current production, he may reach the South Side of Chicago sooner rather than later. So, how long should we expect him to be in Triple-A? Tough to say, but Antonacci played only 14 games in Triple-A before his promotion. With limited competition at the MLB level, Montgomery could realistically earn a call-up around the All-Star break, if not earlier.

For fantasy purposes, Montgomery should already be on your radar in 15-team leagues. Once he is promoted, he should be rostered in 12-team formats as well, especially in leagues that value on-base percentage.

Joe Mack, C, Miami Marlins (2% rostered)

Level: MLB

2026 Stats: 103 PA, .244/.388/.378, 10 R, 3 HR, 9 RBI, 1 SB, 19.4% BB%, 21.4% K%, 116 wRC+

First @MLB hit ✅
First @MLB RBI ✅

Joe Mack has arrived pic.twitter.com/rwkq2XWHeD

— Miami Marlins (@Marlins) May 5, 2026

Mack is widely regarded as one of the game’s better defensive catching prospects and should give the Marlins’ pitching staff an immediate boost. Offensively, he profiles as a slightly below-average hitter, but has shown steady improvement in recent years. After hitting just .217/.324/.303 over his first three professional seasons, the left-handed hitter made a key adjustment by attacking fastballs earlier in counts, which helped him tap into more power.

That change paid off, as he posted a 136 wRC+ across High-A and Double-A in 2024, followed by a 120 wRC+ in Triple-A last season. For fantasy purposes, Mack is worth rostering in 15-team, two-catcher formats, but expectations should be tempered. He’s likely to split time behind the plate with Liam Hicks, and when he does play, he's projected to hit in the bottom third of the lineup.

He’ll also spend half his games at loanDepot park, one of the more pitcher-friendly environments in MLB. ATC projects the 23-year-old for nine home runs and three stolen bases with a .220/.283/.373 slash line, along with a 28.3% strikeout rate and a 7.4% walk rate. If you’ve been hit by injury at catcher or need an upgrade at C2, Mack is worth monitoring, but don’t overspend in FAAB or move on from players with more upside.

Fantasy Baseball Pitcher Prospects To Target

Noah Schultz, SP, Chicago White Sox (46% rostered)

Level: MLB

2026 Stats: 21 IP, 2.53 ERA, 1.03 WHIP, 23.5% K%, 14.1% BB%, 3.56 FIP

If you’re anything like me, you’ve probably dealt with multiple pitching injuries and are looking for someone to help fill the gaps. Look no further than Noah Schultz. We touched on Schultz just a few weeks ago before his promotion, but his roster rate suggests not everyone is sold yet. Since being called up, the 6-foot-10 southpaw has been steady, especially in a season where starting pitchers on the waiver wire have been highly volatile.

The 22-year-old's four-seam fastball has generated a 28.6% whiff rate, while both his sweeper and slider have held opponents under a .182 expected batting average. Here is a breakdown of his arsenal since he joined the majors.

Overall, he grades out with a 100 Stuff+, 99 Location+, and 97 Pitching+. In other words, his profile suggests he’s an average pitcher, and at this point, that’s exactly what you need while waiting for your injured starters to return. He’s also done a solid job limiting hard contact, allowing just one home run so far.

Under the surface, however, he carries a 4.71 SIERA and a .173 BABIP, so a blow-up start or two wouldn’t be surprising. For now, it’s best to use Schultz in favorable matchups, and a few are coming up. Over the next few weeks, he’s scheduled to face the Los Angeles Angels (116 wRC+ vs. lefties) in Anaheim, the Kansas City Royals (77 wRC+) at home, the Seattle Mariners (118 wRC+) in Seattle, and the Giants (79 wRC+) in San Francisco.

While the Angels and Mariners are tougher matchups on paper, both teams strike out at high rates against left-handed pitching. The Royals and Giants, meanwhile, rank near the bottom in most offensive categories. In addition, all four games come in pitcher-friendly parks, especially T-Mobile Park in Seattle and Oracle Park in San Francisco.

Schultz is worth rostering in all 12-team leagues and appears to be locked into the starting rotation for the foreseeable future. That said, it’s still best to use him selectively until his command improves and his walk rate comes down.

Logan Henderson, SP, Milwaukee Brewers (24% rostered)

Level: MLB

2026 Stats: 8 IP, 4.50 ERA, 0.88 WHIP, 36.7% K%, 3.3% BB%, 0.77 FIP

Veteran starter Brandon Woodruff hit the injured list over the weekend, opening the door for right-hander Logan Henderson to be called up. Henderson has been strong in Triple-A and now appears locked into the rotation for at least the next few weeks, and possibly longer, given Woodruff’s injury history. In Triple-A last season, Henderson earned a late call-up by posting a 3.59 ERA and 3.77 FIP, along with a strong 28% strikeout rate and a solid 7.7% walk rate.

This marks his third stint in the majors, and he has impressed so far. Over 27 1/3 big league innings, the 24-year-old from Montgomery, Alabama, has posted a 2.30 ERA, 2.92 FIP, and 1.06 WHIP, with 36 strikeouts and just nine walks. Looking at his profile, Henderson is more known for command and pitchability than overpowering stuff. His 101 career Stuff+ is around league average, but his 108 Location+ better reflects his strength: the ability to spot pitches effectively and keep hitters off balance.

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From an arsenal standpoint, Henderson leans heavily on a 91–95 mph fastball and a low-80s changeup with heavy fade and movement. The changeup is his best weapon, and he uses it effectively against both lefties and, more importantly, righties. He’ll also mix in a slider and cutter, though those offerings primarily serve to keep hitters off balance. Overall, Henderson profiles as a changeup-heavy, efficient strike-thrower.

Now it’s fair to question his long-term upside given his limited fastball velocity and reliance on just two primary pitches to get outs. However, for fantasy, he’s still worth rostering in 12-team leagues thanks to his potential for solid ERA and WHIP numbers, along with some strikeout upside. It also helps that Milwaukee’s coaching staff has consistently shown an ability to maximize pitchers, particularly through pitch design and usage.

As a result, it’s not out of the question for him to take another step forward. On the offensive side, the Brewers’ lineup should give him plenty of opportunities to pick up wins. Milwaukee was one of the best teams in baseball last year and has opened this season at 18–14. Henderson’s upcoming schedule includes a home start against the New York Yankees, followed by a matchup with the Minnesota Twins if he remains in the rotation.

Henderson should be rostered in all leagues, but he’s best used in favorable matchups. For example, you may want to sit him against the Yankees, who have been the hottest lineup in baseball recently, posting a league-leading 136 wRC+ over the past few weeks. However, if he performs well in that outing, he could be a must-start pitcher going forward.

More Fantasy Baseball Prospects and Rookies