Unfortunately, David Wright is on the disabled list and won't be back for quite some time. The Mets announced that their captain will rest from baseball activity for six-to-eight weeks because of a herniated disk in his neck. Wright came into the season knowing he'd have to manage spinal stenosis, which caused him to miss a huge chunk of the 2015 season, but now he has a new injury to work his way back from while still managing the existing one.
There's no doubt that Wright's bat will be missed. In 37 games and 164 plate appearances, he hit .226/.350/.438 with 7 home runs and a 121 wRC+ over the first two months of this season. The batting average probably turns some people off a bit, but he's gotten on base and hit for power, both of which are more important when it comes to a team's ability to scores runs.
In the best-case scenario, Wright would return sometime in August. If things linger more than expected, he might not be back until September. The Mets have to plan for what's already scheduled to be a long-term absence. Let's look at their options at third base going forward.
In the organization
There's no ideal solution on the major league roster or in the upper minors right now. Wilmer Flores is going to get the first shot at the job, and while he's a fan favorite, he's struggled to establish himself as a major league hitter. His line this season—.214/.295/.314—shouldn't be taken too seriously since he's made just 78 plate appearances. But he hit .263/.295/.408 with 16 home runs in 510 plate appearances, which translated to a 95 wRC+. Major league third baseman have collectively hit .264/.334/.440 this season, which would leave Flores below average at the position even if he were to match his 2015 line.
Beyond Flores, there's a collection of players who are probably not everyday big league players: Eric Campbell, Matt Reynolds, T.J. Rivera, and Danny Muno. Campbell and Reynolds are on the Mets' 40-man roster, while Rivera and Muno are not. None of the four should be considered an everyday solution on a team that's competing for the National League East title this year.
After that group of players, the Mets don't have any great prospects at third base who would warrant a Michael Conforto-esque call-up. Until the Mets acquire a player from outside the organization, this should be Wilmer Flores's job to lose—assuming he's not needed at first base on a regular basis.
All of this assumes the Mets won't move Neil Walker to third base and call up 22-year-old Dilson Herrera to play second regularly. In his brief time in the big leagues over the past two seasons, he's hit six home runs in 169 plate appearances with a .215/.308/.383 line and 97 wRC+. He's hitting well in Las Vegas, and the fact that he held his own at such a young age with the Mets is impressive.
Walker has played just a handful of major league games at third, all of which came back in 2009 and 2010, and he's been everything the Mets could have hoped for after acquiring him for Jon Niese in the offseason—which is somehow still a thing that happened. If he were willing to play third, though, it could be the Mets' best option for filling the void left by Wright's injury.
Outside the organization
If there isn't an ideal solution within the Mets' organization, maybe there's one elsewhere. Let's start with the list of third basemen with contracts set to expire at the end of the 2016 season, via MLB Trade Rumors:
Daniel Descalso (30)
Stephen Drew (34)
David Freese (34)
Chris Johnson (32)
Kelly Johnson (35)
Casey McGehee (33)
Martin Prado (33)
Justin Turner (32)
Luis Valbuena (31)
It's a relatively uninspiring list. David Freese is hitting well and playing for the Pirates, a team that is very much contending for the postseason. He's probably not going anywhere.
Kelly Johnson, a familiar face from his time with the Mets after they traded for him and Juan Uribe last season, is back with the Braves. He's almost certainly available again, though he's struggled quite a bit this season, with a .222/.281/.299 line and just one home run in 128 plate appearances. He's probably going to hit better than that the rest of the way, though. It'd sting a bit to have to trade for a player for the second time in a calendar year, but he presumably wouldn't cost too much.
Martin Prado is a similar player in that he's played multiple infield positions and been a bit better than a league-average over the course of his career. He's with the Marlins now, in the final year of a four-year contract, and hitting .305/.342/.376 on the season. He's hit nine or more home runs every season going back to 2009 but has hit just one so far this year. The Marlins are in the contention mix at the moment, but it's not inconceivable that he could be available in the coming weeks.
Justin Turner is back to hitting like Justin Turner, which doesn't mean he'll stay that way but is making his production over the past two years look more like the aberration than the norm. It's also hard to imagine the Mets trading for him at this point after non-tendering him a couple of years ago and not seeming to think too highly of him at the time.
If the soon-to-be-free-agent crop offers too little, let's take a quick look around the league at the third basemen playing for teams that are clearly not contending in 2016.
The Twins are as out of the playoff race as any team in baseball. Miguel Sano isn't playing third base for them right now, but he's also the cornerstone of their team as it tries to move toward contending. He's clearly staying put.
But Trevor Plouffe, who has manned third base for Minnesota for the past few years, is under control through the 2017 season. Right now, he's also blocking Sano at third base, and Sano is attempting to play the outfield instead. Plouffe hasn't been great so far this year, as he's hit .254/.283/.370 with a 74 wRC+, but he's a career .245/.307/.417 hitter with a 98 wRC+. Defensive metrics have rated him a bit above or below average, depending on your preferred metric. Earlier in his career, he played a bit at the other infield positions, and the total package here looks more or less like the Twins' version of Kelly Johnson.
The Twins also have Eduardo Escobar, who has primarily been a shortstop in his big league career but has spent some time at third base, too. He was a bad hitter in the big leagues until the last two seasons, during which he was a tick above a league-average hitter. In total, he hit .268/.312/.425 between 2014 and 2015. He's off to a terrible start this year, with a .248/.279/.295 line, but he's 27 years old and controlled through 2018. Next year is his second year of arbitration eligibility.
Los Angeles Angels
The Angels' current third baseman is Yunel Escobar, who has bounced around over the years and is now 33 years old. For his career, he's hit .282/.351/.387 with a 103 wRC+. He's been a much better hitter than that recently, with a 120 wRC+ last year for the Nationals and a 121 wRC+ so far this year for the Angels. He played shortstop earlier in his career but has been at third base exclusively since last season began, and he's making $7 million this season with a $7 million option for 2017.
Former Mets farmhand Jefry Marte is with the Angels right now, too, and he's hit well in an extremely small sample at the major league level. But he's hit .265/.354/.407 in Triple-A—playing in the Pacific Coast League—this year.
The A's are playing Danny Valencia at third base these days, and there's a chance he's really a better hitter now than he was for most of his major league career. Now 31 years old, he got his start with the Twins and played for the Red Sox, Orioles, Royals, and Blue Jays before he landed in Oakland. For his career, he's hit .273/.315/.438 with a 105 wRC+, but he broke out last year and has been a much better hitter since then.
Over the course of his career, Valencia has feasted upon lefties and struggled against righties. But since the beginning of last season, he's fared well against both left- and right-handed pitchers. He's making just north of $3 million this year and is under control next season, which is his third and final year of arbitration eligibility.
The Brewers have been playing Aaron Hill at third, and so far, he's having a good year. After putting together a couple of very good years at the plate with the Diamondbacks in 2012 and 2013, Hill was well below league average for them in 2014 and 2015. With Milwaukee, he's hit .273/.349/.424, which is good for a 107 wRC+. There's some risk that the 34-year-old will revert to his 2014-15 form, but he presumably wouldn't cost a ton to trade for.
San Diego Padres
San Diego's Yangervis Solarte, a familiar face in New York from his time with the Yankees, has been thrown out there by some Mets fans. He's played the bulk of his major league career at third base, and in each of the past two seasons, he's hit above league average. He's off to a blistering start on a very bad Padres team, as he's hit .329/.413/.586 with four home runs. That's likely unsustainable, but Solarte is 28 years old and under control through 2019. Even if the assumption is that he'll just be a decent hitter instead of the one he has been this year, he might not be cheap to acquire.
The Phillies have Maikel Franco at third, and he's one of the bright spots of their rebuild thus far, as he had a very good rookie season last year. The Braves have the aforementioned Kelly Johnson and the 31-year-old Adonis Garcia, who hit well in limited playing time last year but has struggled so far this year. And the Reds have Eugenio Suarez at third, who is still young and has hit 26 home runs over 152 games since the beginning of last season.
There aren't many exciting names out there, but for the most part, the players above are well-established major league hitters. Considering the Mets are currently rolling with a roster that includes Flores, James Loney, Ty Kelly, and Matt Reynolds as the corner infield options, it would make sense to go and get someone from outside the organization, as they did last year when they traded for Juan Uribe and Kelly Johnson—a move that ensured their major league roster was full of major league players.