2026 Fantasy Baseball Sleepers: First Base

Welcome to a brand new series at RotoWire which features our favorite sleepers by position. Over the next two weeks, we'll share three sleepers and one deep sleeper at every position on the diamond. For the purposes of this series, here's how we're defining "sleeper" and "deep sleeper":

• Sleeper: a player being drafted between picks 150 and 350 who could significantly outperform his draft price
• Deep Sleeper: a player being drafted after pick 350 who could significantly outperform his draft price

After beginning with the catcher spot, let's take a look at the top sleepers at first base for your 2026 fantasy baseball drafts.

Note: the average draft position in this article is taken from all Draft Champions leagues which have drafted over the past month.

Best 2026 First Base Sleepers

Sal Stewart (ADP 205, 1B 20)

The 2025 campaign was overall a strong one for Stewart. Across three levels, the 22-year-old slugged 25 homers over 136 games while swiping 17 bases, and while his ratios didn't hold up in a September taste of the majors, his .309/.383/.524 slash line between Double-A and Triple-A came with a stellar 15.6 percent strikeout rate. Stewart's Statcast page would have been redder than his ballcap if he'd had enough plate appearances in MLB to quality, with his 95.4 mph average exit velocity putting him in the company of guys like Aaron Judge and Shohei Ohtani.

Even with all that working in his favor, the 32nd-overall pick in the 2022 draft still has some hurdles to overcome. His 25.9 percent strikeout rate over his 58 big-league plate appearances is a little disconcerting, and a shaky spring would open the door for the likes of Spencer Steer or even Christian Encarnacion-Strand to push him for the starting job at first base. The Reds' 1B/3B/DH picture got more crowded with the Eugenio Suarez signing, so Stewart will need to earn his spot. If he does claim the starting assignment though, a likely spot in the heart of the batting order behind Suarez and Elly De La Cruz would be a sweet one when it comes to RBI opportunities.

With his mediocre September line dampening the hype just a touch, Stewart's upside makes him a potential league-winner in 2026 drafts at his current price tag.

Kyle Manzardo (ADP 237, 1B 21)

Manzardo's first full season in the majors was a successful one, for the most part. The 25-year-old launched 27 homers in 531 plate appearances, showing that his power gains in 2024 were no fluke. While his batting average remained low at .234, his barrel rate, hard-hit rate and walk rate all ticked up from his 2024 debut, and he improved his slash line to .256/.338/.473 in the second half. That average could end up being at the low end of his range once he's fully established.

The Guardians' offseason also offers some potential helium for Manzardo's production. Carlos Santana is no longer in the 1B/DH mix, leaving Manzardo competing with the unproven C.J. Kayfus for playing time at first base. Kayfus does have a slightly better defensive reputation, but Manzardo should be a fixture at one of those two positions. Cleveland's gone all in on a youth movement for their offense, with Travis Bazzana, Chase DeLauter and George Valera among the prospects the team is counting on to take a leap forward and raise the ceiling on the entire lineup. Manzardo won't need all of them to click to get more opportunities to drive in runs than he saw last year, when he managed just 70 RBI despite mainly hitting fourth or fifth in the order behind Jose Ramirez.

Manzardo even gets a "best shape of his life" rub, as he's reported to have added 14 pounds of good muscle to his frame in an effort to stay healthier, make harder contact against same-handed pitching and add a little more oomph to his flyballs. His package as a hitter points to a potential 40-homer campaign at some point in his career, and while that may not happen in 2026, a big power and RBI spike isn't off the table.

Miguel Vargas (ADP 274, 1B 25)

Could this finally be the season Vargas emerges as the player it seemed like he was on track to become when he was a top prospect with the Dodgers? It's been a rough few years for the 26-year-old, who's dealt with injuries, a trade from the best organization in the majors to one of the worst, and a constantly shifting defensive profile during that time. Vargas finally seemed to find a little stability in 2025, and while his .234/.316/.401 slash line with 16 homers and six steals in 138 big-league games were nothing special, those numbers only scratch the surface of his upside.

Vargas' strong plate discipline from the minors finally joined him in Chicago last season as he posted an 89th percentile chase rate, while his average exit velocity, hard-hit rate and barrel rate also took steps forward, although they still lagged behind the rates he was putting up as a Dodgers farmhand a few years ago. Conversely, his 84th percentile sprint speed fell to the 51st percentile in 2025, but it's yo-yo'ed ever since he got to the majors, and he's still young and athletic enough that another rebound can't be dismissed. Vargas swiped 16 bags in 21 attempts for Triple-A Oklahoma City in 2022, although Will Venable wasn't handing out a lot of green lights last year in his first season at the helm for the White Sox.

The offseason signing of Munetaka Murakami will likely push Vargas back to third base to begin the year, but if the NPB import struggles defensively, he could wind up at DH most days, opening the cold corner back up. The White Sox's lineup still looks very second-division, but the support for Vargas could get a noticeable bump compared to 2025 if young players like Colson Montgomery and the catching duo of Kyle Teel and Edgar Quero continue their ascent, putting the team's offense closer to middle of the pack than last year's bottom-four finishes in runs scored and team OPS.

Deep Sleeper

Coby Mayo (ADP 485, 1B 38)

When sifting for potential picks late in a deep draft, it's important to prioritize upside above all else. Using a pick on a low-ceiling guy with a safe starting job doesn't move the needle for your roster; finding a guy who's just one trade or injury away from getting a chance to shine just might. Mayo is a perfect example of the latter type of player.

The 24-year-old hasn't been able to keep pace with a lot of his fellow Orioles prospects, and over 102 big-league games the last two years, Mayo has managed just a .201/.285/.349 slash line and 11 homers with a 31.2 percent strikeout rate. That's a far cry from the numbers he was posting in the minors — he clubbed 29 homers with a .974 OPS between Double-A and Triple-A in 2023, and followed that up with 22 homers and a .926 OPS in only 89 Triple-A games in 2024. Mayo's plate discipline was solid, and his bat speed (74.7 mph in 2025, comparable to Corbin Carroll and Elly De La Cruz) gives him plus-plus power upside, if he ever gets a chance to settle in and show it. Mayo teased that ceiling last September, slashing .301/.393/.548 in 84 plate appearances with five homers as he got everyday run for a team that disappointingly found itself out of the playoff picture.

Mayo's path to at-bats at first base was closed when Baltimore signed Pete Alonso this offseason, and between Samuel Basallo, Tyler O'Neill and Ryan Mountcastle, the competition for playing time at DH is already fierce. There's simply no room for Mayo to flourish on the current Orioles' roster, but that just makes him one of the organization's top trade chips as it hunts for pitching or other upgrades, and a return to postseason contention in 2026.

Who is your top sleeper at first base for 2026? Let us know in the comments below.