Chien-Ming Wang was making progress, again. He was beating Roy Halladay in the sixth inning, and with another out, he could call Saturday’s game his longest outing of a difficult season. But his shoulder would not let him.

Wang allowed a home run, then threw a ball that was startlingly slower than it should have been. He left Yankee Stadium for a hospital, slipped into a magnetic resonance imaging tube and returned before the game ended. He watched from the clubhouse as Jorge Posada singled home the winning run in the 12th inning of the Yankees’ 6-5 victory over the Toronto Blue Jays.

The Yankees have won 9 of 10 and moved to a game behind Boston for first place in the American League East. Posada ducked a decoy pie in the face from Joba Chamberlain after the game, only to be slammed by A. J. Burnett. Yet the loss of a starter, even one like Wang who has struggled to find his inner ace, tempered the fun.

The Yankees said Wang had a shoulder strain and bursitis, and Manager Joe Girardi acknowledged he would need rest. That almost certainly means another trip to the disabled list for Wang, who missed most of last season with a foot injury, the effects of which bled into this season.