He was hurt. He came back to play for a team that didn't need him to win. It was weird.
There is a storm of controversy and hot fiery takes rampaging through the Tri-State Area at the moment, centered around the New York Mets and their ace pitcher, Matt Harvey. Once you get past all the hysterics, however, you might notice that all of the players involved are acting fairly rationally. The front office wants their best pitchers on the mound for the stretch drive and the playoffs, while Harvey (and his agent) are concerned about re-injuring his arm after Tommy John surgery.