As of today, the Mets have managed to build a 7.5-game lead on the second-place Nationals. This lead has been forged by an improved Mets team in the wake of the trade deadline, helped in no small part by a Nationals team that hasn't seriously threatened the division lead for some time.
As a result, the Mets have the luxury of tinkering with their roster as the season wanes. With just nine games to go and a magic number of three, the race for the National League East title is virtually locked up, and the Mets are managing in-game decisions accordingly.
Case in point, the Mets allowed Steven Matz to continue pitching in Thursday night's game despite a high pitch count and his having given up several hits in the sixth inning. Matz has a low innings count for the season due to time spent on the disabled list, and the Mets' relative comfort in the standings afforded them the opportunity to push their young starter a bit. The Mets aren't so far atop the standings that they'd gleefully throw potential wins into the abyss, but they're in a position to assume some extra risk.
It wouldn't be surprising to see the Mets diverge from their game plan over the next week and a half. They can—and should—allow lefties like Michael Conforto and Lucas Duda to see more playing time against left-handed pitchers. They could also see how one or more of their starters feels coming out of the bullpen, a role that could be particularly useful in the playoffs.