Russell Martin hit a hard grounder off Alvarez's leg in the fourth inning Monday night and the ball caromed into shallow right field for an RBI single. Alvarez hobbled over to the first base line and bent over in pain. The right-hander was checked by a trainer and walked slowly off the field.
X-rays were negative and he is day to day.
Aaron Laffey came in to pitch for the banged-up Blue Jays and was given all the time he needed to warm up.
Alvarez also was checked by the trainer in the second inning after Eric Chavez's comebacker deflected off his pitching hand for an infield single. He threw a couple of warmup pitches and appeared to be OK.
Alvarez lost his previous four starts and hasn't won since July 28 against Detroit.