Brett Baty's First Base Experiment Is Exposing a Critical Mets Flaw
When the New York Mets decided to let Pete Alonso walk to the Baltimore Orioles last offseason, the front office had a plan — or at least the outline of one. Brett Baty would shift from third base to first, Jorge Polanco would sign a two-year, $40 million deal to handle the position, and Mark Vientos would rotate in as needed. On paper, it was a patchwork solution. Nearly two months into the 2026 season, that patchwork is coming apart at the seams.
Baty, who started at first base on Friday, May 1 against the Los Angeles Angels while Vientos sat out, remains one of the most closely watched players in the National League — not because of what he's doing, but because of what the Mets are desperately hoping he'll start doing. The 24-year-old drew the start batting fifth, carrying with him the baggage of an 0-for-10 slump he only recently snapped. The position he now plays wasn't his by design. It was his by default.
This is the story of a franchise that, as one NL scout bluntly summarized, "took a strength and made it a weakness."
How the Mets Got Here: The Alonso Departure and What It Cost
Pete Alonso wasn't just a first baseman for the Mets. He was an identity. For six seasons, his thunderous left-handed swing defined what Citi Field offense could look like — a middle-of-the-order anchor who hit for power, commanded the strike zone, and showed up in October. In 2025, the Mets' first base group posted a .861 OPS, second-best in all of Major League Baseball. That production was almost entirely Alonso.
When Alonso signed with Baltimore in the offseason, the Mets chose not to match or exceed the offer. General manager David Stearns decided the money was better deployed elsewhere and that internal options could adequately fill the hole. The thinking wasn't indefensible in isolation — Baty had tools worth developing, Vientos had shown flashes of power, and Polanco was a professional hitter with a track record.
But the sum of those parts has been far less than the whole they replaced. According to reporting on the Mets' first base situation, the group of Baty, Vientos, and Polanco has combined for the fourth-worst OPS at first base in MLB at .581. FanGraphs has assigned the trio a collective WAR of -0.5, the second-lowest mark in baseball. That's not underperformance — that's a category collapse.
Brett Baty's Position Switch and Its Growing Pains
Baty's relocation to first base was announced during spring training 2026, framed as a way to unlock more of his offensive potential by removing the defensive complexity of third base. The logic was straightforward: if his bat is the asset, simplify everything else around it.
It hasn't worked out that way. Baty, who entered the season as a former top prospect still trying to establish himself at the major league level, has struggled both at the plate and around the bag. On April 29, 2026, he ended an 0-for-10 slump by going 1-for-3 in a lopsided 14-2 loss to the Washington Nationals at Citi Field — a result that said almost everything about where the Mets are right now. Snapping a cold streak in a 12-run blowout loss provides little comfort.
Defensively, the transition to first base carries its own learning curve. While first base is generally considered less demanding than the hot corner, it requires specific footwork around the bag, comfort receiving off-target throws, and instincts around the 3-6-3 double play. Baty is still developing all of that while simultaneously trying to find consistency against major league pitching — a dual burden that would challenge any young player.
Manager Carlos Mendoza has been measured in his public assessments. He's acknowledged that the Baty-Vientos arrangement has "handled the position fine" in a fielding sense, but has offered a notably transparent concession: "Offensively, we expect more." That's not exactly a ringing endorsement heading into May.
The Polanco Factor: A $40 Million Puzzle Piece That Doesn't Fit
The Mets' first base plan was never solely about Baty and Vientos. Jorge Polanco, the veteran infielder who spent several productive seasons with the Minnesota Twins, signed a two-year, $40 million contract with the understanding that he would transition to first base in New York.
That plan has been derailed almost entirely by injury. Polanco has been absent for most of the early 2026 season, leaving the Mets without the steady veteran presence they paid significant money to acquire. When a $20 million-per-year player can't play, the depth chart gets stressed quickly — and in New York's case, it's exposed just how thin the organization's first base contingency actually was.
Polanco's history as a second baseman also raised legitimate questions about whether the transition to first base would be seamless. While infielders generally adapt to the position over time, asking a 32-year-old to fundamentally change his defensive profile while also returning from injury is a significant ask. The Mets bet $40 million on that outcome. So far, that bet is sitting dormant.
Vientos and Baty: A Rotation With Questions
While Baty has drawn more scrutiny because of his prospect pedigree and the louder expectations attached to it, Mark Vientos has actually been the more functional half of New York's first base timeshare in recent weeks. CBS Sports reported that before sitting out Friday's game, Vientos had reached base safely in six of his last seven games, going 6-for-22 (.273) with two RBI over that stretch. For a team starving for offensive production at the position, that's not nothing.
But Vientos sitting on May 1 — with Baty getting the start against the Angels — illustrates the ongoing challenge. Neither player has fully seized the job. The Mets are managing a platoon, hoping one of them catches fire while not entirely giving up on the other. It's a reactive posture masquerading as a strategy.
What's notable is that Vientos's recent run of better at-bats came against a variety of pitching, which suggests real improvement rather than a hot week against weak competition. The question now is whether Mendoza's lineup decisions will reflect that momentum or continue to treat both players as equals in a competition that one of them may already be winning.
What This Means: A Front Office Accountability Moment
It's easy to pile on Baty, and the temptation is understandable given the circumstances. He's young, he's struggling, and he's occupying a position at a roster spot that was recently held by one of the game's premier power hitters. The comparison is inherently unfair and structurally inevitable.
But the more important story here is a front office decision that has not paid off. The Mets chose to let Alonso leave. They chose to build a committee at a premium offensive position. They committed $40 million to a player who has barely played. Each of those decisions was defensible in isolation, but their combined failure has produced a first base group with the second-lowest WAR in baseball — and that's a front office problem as much as a player problem.
The NL scout's assessment that the Mets "took a strength and made it a weakness" is pointed precisely because it's accurate. First base was a reliable part of a lineup that made the postseason in 2024 and came close in 2025. Entering 2026, it has become a drain. The ripple effects on the rest of the batting order are real — lineup construction gets harder when the first base spot is producing negative value, middle-of-the-order protection is thinner, and Mets pitchers are working with less room for error on the offensive side.
Whether this situation is correctable before it derails the season remains to be seen. The Mets could pursue a trade for a first baseman — the market historically opens up around the deadline — or they could commit more fully to Vientos and give him a defined starting role rather than splitting time. Either way, the current path of rotating Baty and Vientos while waiting for Polanco isn't producing results, and the standings don't wait for internal development timelines.
Broader Context: The Mets' Offseason Philosophy Under Scrutiny
This situation fits within a larger pattern of questions about how the Mets are allocating resources. David Stearns took over with a mandate to build a sustainable winner — one less dependent on Steve Cohen writing enormous checks to solve every problem. Letting Alonso walk, rather than paying what it would have taken to retain him, was a signal that the organization believed it had other paths forward at the position.
Those paths have not opened up. And while the season is still young — 27 games into a 162-game schedule — the first base situation represents a genuine structural weakness rather than a slow start by capable players. A .581 OPS and -0.5 WAR are categories you usually see from teams with true holes, not from teams with legitimate alternatives.
For Mets fans watching a once-dominant position turn into a liability, the frustration is compounded by seeing Alonso thrive in Baltimore with a new audience and a new team. That storyline will follow this front office all season unless someone — Baty, Vientos, or an eventual acquisition — forces a rewrite.
FAQ: Brett Baty and the Mets' First Base Situation
Why did the Mets move Brett Baty to first base?
The Mets shifted Baty from his natural position of third base to first base during spring training 2026 as part of their restructuring following Pete Alonso's departure. The move was designed to simplify Baty's defensive responsibilities and allow the team to focus on developing his offensive potential at a less demanding position.
How has the Mets' first base group performed in 2026?
The combination of Baty, Mark Vientos, and Jorge Polanco has been one of the worst-producing first base groups in MLB. Their collective OPS stands at .581, the fourth-worst at the position, and FanGraphs has credited the group with a -0.5 WAR — second-lowest in baseball. This is a dramatic decline from 2025, when Pete Alonso led the Mets to a .861 OPS at first base, second-best in the majors.
What happened to Jorge Polanco?
Polanco, who signed a two-year, $40 million contract to play first base for the Mets, has missed most of the 2026 season due to injury. His absence has placed nearly all of the burden on Baty and Vientos, two players who are better suited as parts of a three-man rotation than as everyday starters at a critical offensive position.
Is Brett Baty going to keep playing first base?
As of May 1, 2026, Baty remains in the first base rotation alongside Vientos, with manager Carlos Mendoza making day-to-day lineup decisions based on matchups and recent performance. Whether that arrangement continues through the full season depends on how both players perform and whether the Mets choose to make a move in the trade market to address the position.
Where is Pete Alonso now and how is he playing?
Pete Alonso is in his first season with the Baltimore Orioles, having signed with them after leaving New York in the 2025 offseason. His departure left the Mets without the anchor of their lineup and the centerpiece of their first base production — a void that has proved significantly harder to fill than the organization anticipated.
Conclusion: A Season-Long Test for Baty and the Mets
Brett Baty's story in 2026 is not just about an individual player finding his footing. It's about a franchise making a calculated bet at a key position and watching it come up short so far. The 0-for-10 slump, the defensive learning curve, the committee approach, the injured veteran, the departed superstar — all of it converges at first base, and all of it puts pressure on a young player who is still figuring out who he is at the major league level.
There is time to course-correct. Polanco could return healthy. Vientos could break out. Baty could make the mechanical adjustments that unlock his potential. The trade deadline exists precisely for teams that identify a structural weakness mid-season and have the assets to address it. None of those outcomes are guaranteed, but none are closed off either.
What isn't debatable is the current state of affairs: the Mets took one of their most reliable offensive positions, rebuilt it from scratch around unproven pieces, and are paying the statistical price. Until one of those pieces proves it belongs — really proves it, over a stretch of games that matters — the ghost of Pete Alonso will hang over every at-bat at Citi Field's first base bag.
