In the bandbox of Citizen’s Bank Park on Wednesday, Mets reliever Hansel Robles entered a Mets-Phillies tilt in a precarious situation. The hard-throwing righty came in to bail out starter Zack Wheeler in the sixth inning with the bases loaded and Philadelphia’s stellar third basemen, Maikel Franco, at the plate. A pitch later, this happened:

jstolnis: Maikel Franco may be heating up, fam. The Comcast … MLB Baseball: Mets at Phillies https://t.co/3CFT9dsaHW pic.twitter.com/GJuyyGhA5d

— FanSportsClips (@FanSportsClips) April 13, 2017

Robles was appearing in his third straight game, during which he logged almost three innings of strong work, one pitch notwithstanding. Suddenly, a five-run cushion turned into a one-run nail-biter, and the Mets and their bullpen had a lot of work to do.

It’s been a familiar refrain for Flushing’s Very Own through the first ten games of the season. After last night’s 16 inning marathon in Miami, The Mets bullpen has now logged a league leading 43 1/3 total innings over 42 collective appearances. Even without a stat-skewing elongated extra innings game, the Mets’ pen would rank in the top third of the Majors in overall usage and usage per game.

A taxing season on the bullpen was expected given the way the Mets have managed their crop of high-potential starters since Matt Harvey broke through in 2012. New York’s top contributing relievers by innings pitched, Robles, Fernando Salas and stand-in closer Addison Reed, account for about half the innings pitched from the pen. This isn’t rare—relievers aren’t used the same and innings pitched is affected by batting order, handed-splits and leverage (for example, Paul Sewald, the Mets reliever who was just optioned to Triple-A to make room for Juan Lagares, had only pitched in 7- and 10-run games, respectively). But the volume of appearances is adding up. The Mets are the only team in baseball with four relievers who have logged six or more appearances and contributed six or more innings pitched so far in 2017. Robles has now pitched four straight nights.

The contributory stress factor on the pen is starter’s longevity, though the starting rotation has mostly done what the organization likely expects of them. Although Robert Gsellman was unable to get out of the fifth inning last night, the Mets are at about the league median in starters’ innings pitched. In an era of expanded bullpen use, it’s unfair to suggest New York’s starting rotation isn’t doing enough. Stats are jumbled this early in the year, and the margin between top-3 contribution and bottom-15 contribution is about one extra out unconverted. The starters are one out more per game away from averaging six innings a start in a league where six-per-game would be up there with the league leaders.

Really, if there are concerns to be had, it’s in what may lie ahead.

Bullpens—and managers—look for non-scheduled nights off. A game where the starters go deep into the night in the midst of three or four straight series is a blessing bordering on a necessity. But that kind of night may not exist in New York’s rotation.

Harvey is coming back from surgery and time off. Wheeler is attempting another comeback following Tommy John surgery in 2015. Jacob deGrom had his own arm injury concerns last season. Steven Matz isn’t back yet, and there’s some confusion on his health. Only Noah Syndergaard appears to have a full green light, and his 13 innings pitched over two appearances leads the starting rotation.

Since 2016, the Mets’ big five of Harvey, Syndergaard, deGrom, Matz and Wheeler have completed  seven or more innings in about 30% of starts. With post-injury restrictions probable, the Mets will be leaning on Syndergaard to create a non-scheduled rest day every five games.

Some help is on the way. Jeurys Familia will be back from suspension soon, and the baseball quality of the top half of the bullpen should both rise and deepen. The Mets could also continue to tear the hide off the ball like they did in Philadelphia and drive up scores to the point that the lower half of the pen can be used more often to eat up low-leverage innings. A play made here or there, and the relievers have one or two (or 21, in last night’s case) fewer outs to worry about. Suddenly, the usage would fall closer to league average. In many ways, the problem the Mets face is not a unique one, and could arguably exist at an extreme this early in the season mostly because of some bad luck.

But if the Mets want to convert on some high hopes, they’ll need to keep their starting rotation healthy. And if doing so means having the bullpen grind, Terry Collins will have to make sure they don’t get ground down in the process.

All stats courtesy of FanGraphs and Baseball-Reference and are up to date as of April 13th, 2017.