Unless anything changes over the next eleven months, Dilson Herrera looks like the Mets' long-term plan at second base. In 2015, however, the 21-year-old spent most of his time playing in Triple-A Las Vegas, as Daniel Murphy was the Mets' regular starter at the position. But Herrera, who the Mets acquired in the trade that sent Marlon Byrd and John Buck to the Pirates late in the 2013 season, came into the year as one of the Mets' top prospects. He ranked 9th on our top twenty-five for 2014 and 4th on our list for 2015.
Herrera finished the 2014 season with the Mets, too, after getting called up from Double-A Binghamton in late August when Murphy hit the disabled list. In 66 plate appearances down the stretch, he hit .220/.303/.407 with three home runs and a 106 wRC+. It was an encouraging cup of coffee, though the sample size was obviously very small, and he started the year in Vegas.
He started the year on fire, hitting .370/.402/.506 in 87 plate appearances, an impressive line even in the very-hitter-friendly Pacific Coast League. At the end of April, with David Wright clearly out for the long term, the Mets called him up to play second base while playing Murphy at third. Over the next couple of weeks he didn't hit much, but he did hit the disabled list when he broke the tip of one of his fingers during practice. He started a rehab assignment not long after that and re-joined the Mets in mid-June. He didn't hit much in that stint with the Mets, either, and was optioned back to Vegas at the end of the month.
Herrera stayed with Las Vegas for the remainder of its season and continued to rake. In 268 plate appearances through the end of the team's season, he hit .312/.377/.892. In total, he hit .327/.382/.511 in Triple-A for the season. When that season ended, he got another promotion to the Mets, but with the team closing in on a division title and sporting a much deeper infield than it had earlier in the season, Herrera made just ten plate appearances the rest of the way.
In total, Herrera hit .211/.311/.367 with three home runs and a 92 wRC+ in 103 plate appearances for the Mets. It would have been a delight if he dominated in the big leagues immediately upon any of his promotions, but the season was hardly a failure. His line in Triple-A was impressive, especially considering his age, and he once again held his own in his brief time with the Mets.
Coming off their World Series appearance, the Mets acquired Neil Walker from the Pirates, who will be eligible for free agency following the 2016 season, to play second base regularly. Given that trade, Herrera's path to the majors is at least partially blocked in the short term. He'd seem to be the obvious call-up if Walker were to go on the disabled list, and perhaps he has a shot at playing time in a platoon role with Walker—who doesn't hit nearly as well against lefties as he does against righties—at some point during the season.