Granderson, who entered the night in a career-long 0-for-22 funk, has spent significant time working on his stance and swing this week with hitting coach Dave Hudgens, but the Mets are wary of overreacting to a three-week slump by altering his mechanics too much.
"I don't want to start changing somebody," Collins said. "This guy, this is what he's done. This is what got him here. You start tinkering a little bit, you can really mess him up.
"Due to the fact that we've never really seen him, we didn't study him that much. So what we've tried to do is get as much tape and film and try to compare what's going on now with the past, so we have an idea of maybe when he's coming out of it. But there are really no givens, things that you can see with the naked eye."
As for Nieuwenhuis, Collins simply wanted to give the center fielder some extra playing time to keep him sharp. Young had played every inning of the first 20 games, necessitating a rest, and Nieuwenhuis went into the game with a brief history against Cardinals starter Michael Wacha.
"I just thought tonight would be a good night to get [Nieuwenhuis] in there," Collins said. "[Wacha] can be awfully tough on anyone, but Nieuwey's faced him, so I thought I'd get him in there."
Anthony DiComo is a reporter for MLB.com. Follow him on Twitter @AnthonyDicomo. This story was not subject to the approval of Major League Baseball or its clubs.