2026 First Base Fantasy Baseball Rankings

December 28, 2025

Early first base (1B) fantasy baseball rankings, tiers for 5x5 mixed roto leagues (December updates). Nick Mariano's tiered 1B rankings for 2026 drafts.

Usually, in the past, the first base position was one of the strongest and had plenty of depth for fantasy baseball, but there is a drastic drop in tiers once the top seven are off the draft board. At RotoBaller HQ, we break down the 1B position with our MLB teams' 2026 fantasy baseball first base rankings and tiers for 5x5 mixed roto leagues. These December rankings cover the top 30 first basemen for 2026.

There were several key news, transactions, and rumors about floating trades/signings this offseason involving first base. One of the biggest offseason news stories is that first base slugger Pete Alonso signed a five-year deal with the Baltimore Orioles. The Red Sox acquired Willson Contreras from the St. Louis Cardinals, while the Mets are open to dealing Mark Vientos after signing Jorge Polanco to a two-year deal. Platoon specialists Ryan O'Hearn heads to Pittsburgh while Rob Refsnyder makes his way to Seattle. Josh Bell signed a one-year contract with the Twins. 

The first base rankings below are specifically designed for traditional 5x5 Roto Mixed Leagues, put together by RotoBaller's lead MLB forecaster Nick Mariano. We're also writing fresh articles all throughout the off-season for fantasy baseball prospects, fantasy baseball dynasty, and so much more. Win more in 2026!

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2026 Fantasy Baseball First Base Rankings (December)

Fantasy Baseball First Base (1B) News

Pete Alonso, Baltimore Orioles

Free-agent first baseman Pete Alonso and the Baltimore Orioles are finalizing a five-year, $155 million deal on Wednesday, sources tell ESPN's Jeff Passan. Alonso is leaving the Mets to join the American League East. The 31-year-old right-handed slugger was greeted by a cold market last offseason and eventually re-signed with the Mets for two years and $54 million. Alonso opted out of the final year of the deal after 2025, though, and now he's on the move.

The Polar Bear had a career-high .272 batting average in 2025 in his final year with the Mets and added 38 home runs, a league-high 41 doubles, 126 RBI, and 87 runs scored in 162 games played. Alonso isn't the best defensive first baseman, but he makes up for it by being an elite slugger at the plate. He has cleared 30-plus home runs in all six of his full seasons and has topped 40 homers three times. Alonso gives the Orioles some much-needed thump in the middle of their batting order.

Willson Contreras, Boston Red Sox

The Boston Red Sox are acquiring first baseman Willson Contreras in a trade with the St. Louis Cardinals, sources told ESPN's Jeff Passan. In return, the Cardinals will receive right-hander Hunter Dobbins along with right-handed pitching prospects Yhoiker Fajardo and Blake Aita. According to Passan, the Red Sox will be responsible for $33.5 million of the $41.5 owed to Contreras. Boston had previously pursued Pete Alonso and was rumored to be in on a few other sluggers, but the club now appears to have found its first baseman. Contreras is coming off a season in which he hit 20 home runs while slashing .257/.344/.447 across 563 plate appearances.

With the Cardinals in the middle of a rebuild, the organization did not view Contreras as part of its long-term future. The 33-year-old former catcher is expected to take over for Triston Casas at first base, who struggled to a .580 OPS in 112 plate appearances last season. Casas is often hurt and has missed significant time over the years. Overall, this move is a net positive for Contreras' fantasy value, as he joins a more potent offensive lineup in a substantially better hitting environment.

Ryan O'Hearn, Pittsburgh Pirates

Free-agent first baseman Ryan O'Hearn and the Pittsburgh Pirates have agreed on a two-year, $29 million contract, according to Robert Murray of FanSided. The deal also includes $500,000 in performance bonuses for each season. For the Pirates, O'Hearn should split time between first base and designated hitter and slide right into the middle of the lineup.

In 2025, the 32-year-old left-handed hitter posted a .272 xBA with a 10.7% walk rate while hitting 21 home runs across 544 plate appearances for the Baltimore Orioles and the San Diego Padres. Even though the Pirates aren't a great offensive team, O'Hearn should have the freedom to play every day. Overall, you don't need to bump him up your board much, but you should feel more confident clicking his name on draft day.

Rob Refsnyder, Seattle Mariners

The Seattle Mariners have signed free-agent first baseman/outfielder Rob Refsnyder on Monday, according to Jeff Passan. The deal is reportedly a one-year, $6.25 million contract for the 2026 campaign. The journeyman has spent each of the last four seasons as a part-time player with the Boston Red Sox. Refsnyder mostly plays against left-handed pitching, but has excelled enough at that to carve out a decent career for himself.

Last season, Refsnyder slashed .302/.399/.560 with seven home runs and 25 RBI against southpaws. The 34-year-old figures to be a platoon option at both first base and right field, and possibly sees time at designated hitter, making him mainly an option in AL-Only Leagues.

Matt Mervis, Washington Nationals

The Washington Nationals signed free-agent first baseman Matt Mervis to a minor-league deal on Wednesday. According to Jon Heyman, this is a minor-league deal with a non-roster invite to spring training. The Washington D.C. native will get a chance to catch on as a possible depth option for the Nats.

Last season, Mervis slashed .175/.254/.383 with seven home runs and 14 RBI in 42 games with the Miami Marlins. Mervis came up through the minors with some buzz after slugging 36 homers during the 2022 season. The 27-year-old hasn't been able to put it together at the MLB level, but he could be decent depth for the organization.

Mark Vientos, New York Mets

The New York Mets are open to trading infielder/designated hitter Mark Vientos this winter, sources told Pat Ragazzo of Sports Illustrated. Vientos could draw plenty of interest, as he has four years of club control as a pre-arbitration player. He won't be a free agent until after the 2029 season. However, it remains to be seen how many MLB teams would be interested after Vientos regressed to a .233/.289/.413 slash line with a .702 OPS, 97 OPS+, 17 home runs, 61 RBI, and a -0.2 bWAR in 121 games in 2025.

The year prior, Vientos broke out with 27 long balls, 71 RBI, an .837 OPS, and 3.0 bWAR in 111 games. Brett Baty is likely to be the starter at third in 2026, and the Mets just signed Jorge Polanco to take over at first base to replace Pete Alonso, who signed with Baltimore in free agency. Vientos was able to drop his strikeout rate to a career-low 24.8% in 2025, but he isn't great defensively and still has a lot to prove.

Josh Bell, Minnesota Twins

Free-agent first baseman Josh Bell agreed to a one-year, $7 million deal that includes a mutual option for 2027 with the Minnesota Twins on Monday, sources told Jeff Passan of ESPN. The 33-year-old switch-hitter will play first base and designated hitter for the Twins next season. This is the first big-league signing of the offseason for the rebuilding Twins.

Barring more offseason moves, Bell should see the majority of playing time in Minnesota in 2026 after slashing .237/.325/.417 with 22 home runs, 63 RBI, and 54 runs scored in 140 games with the Washington Nationals. The 6-foot-3, 261-pounder still brings some pop from both sides of the plate, but he has only reached the 30-homer mark once (back in 2019 with the Pittsburgh Pirates), and he doesn't contribute really anywhere else for fantasy managers. Bell will be corner-infield depth in fantasy leagues in 2026 in his first year with the Twins.

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