Young, 30, is perhaps the most intriguing bubble candidate for the playoff roster. A former Met who the team re-acquired last weekend, Young led the National League with 46 stolen bases in 2013. The Mets will use him as a pinch-runner in September, with an eye toward potentially doing the same in October.
Nieuwenhuis and Campbell, both 28, give the Mets pinch-hitting options from the left and right sides of the plate, respectively. The former hit .203 in 87 plate appearances with the Mets this year, with all three of his home runs coming in a single game.