Mark Teixeira took a cutter from Boston's Jon Lester on the inside of his right knee in the first inning last night and was knocked out of the game, and perhaps the rest of the series against the Red Sox.

It's never good to have a position player get banged up, and the options for the Yankees to replace him at first base--Jorge Posada or Nick Swisher, most likely--don't particularly excite, given their recent struggles at the plate. But the Teixeira injury means something more.

Curtis Granderson had contributed mightily to the team in the first two months of the season. When he wasn't carrying the Yankees, he was giving performances that amounted to huge building blocks for the team's success. But he started slumping around May 19--and Teixeira started catching fire around the same time.

This is what is so potent about New York's lineup. As soon as one star player cools off, another one picks it up. But in losing Teixeira for at least a few games, the Yankees lose the player currently most likely to pick the team up and carry them for a win on a given night.

A shift occurred around May 20, and the change was recently cemented as Tex got hot and Granderson cooled, culminating in Teixeira passing his teammate Granderson to nab second place in the most home runs in Major League Baseball on June 5, when his two long balls (and 3 RBIs) powered the Yanks to a 5-3 win over the Angels. It was the sixth time in the last two weeks that Teixeira's production served as the centerpiece for the offense in a Yankee game. Other notable examples include his three-RBI day against the Mets on May 21, and his 2 for 4, two-run contribution on May 27 against Seattle.

Meanwhile, Granderson saw his slugging percentage go from .610 to .583 and his bat go nearly silent from June 1 on. A 3 for 5, four RBI game against Oakland on May 31 and a 4 for 5, two-run performance against Toronto on May 24 were exceptions. At least in late May, Granderson was still getting on base and getting wood onto the ball, but he was slowing down, handing off the team MVP baton to Tex.

And now Teixeira, the man with the hot hand on the team, is out. It's bad news for the Yanks. But given New York's lineup, the question may simply be, who is going to step up and power this team through the next stretch?