The run value of a single is about .25, so that's 30 plays below average, where he didn't make a range out, or about one a week over the full season. That's about the same as the difference between a .260 and .300 hitter, and is generally considered one of those things that you just don't notice through pure observation. Is it possible that you just missed that one play per week that he didn't make, especially when, since you watch so many of the Yankee's game, you don't see a whole lot of the other players out there establishing the average?