McCann entered play on Thursday hitless in his last 13 at-bats, dropping his batting average to .152 with no homers and two RBIs in his first eight games with New York.
The 30-year-old signed a five-year, $85 million contract in December after spending his entire career with the Braves. The Yanks have plenty of reason to believe that his luck will turn; he batted .256 with 20 homers and 57 RBIs in 102 games last season and is the only catcher with at least 20 home runs in each of the last six seasons (2008-13).
"I haven't seen anything where I've seen a big change in his personality," manager Joe Girardi said. "Obviously, I'll continue to watch. I don't think that he's swung the bat as poorly as his numbers have said, but sometimes you run into some hard luck."