Joe Girardi said it was so that Vazquez, 1-3 with a 9.78 ERA in five starts, could have a few extra days to do more bullpen work and "catch his breath."
GM Brian Cashman said tonight before the game that moving Vazquez away from the opener of a three-game set in Fenway Park and into a start in Detroit is mostly common sense.
"Fenway Park is certainly not an easy place to figure yourself out in," Cashman said. "There's a clear recognition that there's major struggling going on here."
Cashman did express an organizational worry about Vazquez's velocity, which has been down several mph from his usual 94-95. Girardi noted that Vazquez hit 94 mph on the Yankees' radar gun on Saturday.
So Vazquez, who did not speak with reporters before the game, will do two bullpen sessions this week: Tomorrow and Friday. He'll likely do a bit more throwing and perhaps some tweaking to his faulty mechanics in those sessions.
Phil Hughes will go on Friday against the Red Sox on normal rest, followed by CC Sabathia and A.J. Burnett. Andy Pettitte moves to Tuesday in Detroit, with an extra day's rest.