"I feel sore," Wang said through a Yankees spokesman. "Of course I'm disappointed. On Tuesday, when I know more, I will talk then."
After pitching five scoreless innings, Wang (8-2) pulled up as he rounded third on Derek Jeter's two-run single during the Yankees' eight-run sixth. He hopped the rest of the way home and pointed to his right foot after scoring. A trainer rushed from the dugout to check on him and Wang was helped off the field. He was relieved in the sixth inning by Ross Ohlendorf.
Getting a rare chance to hit against an NL team, Wang had reached base on a bunt that turned into a fielder's choice.
Mike Mussina, who won Saturday's game, talked to Wang after he was hurt.
"We don't know how bad it is," Mussina said. "We'll wait and see. Before we put him out for a month or two months, let's wait and find out how it looks. We'll find out tomorrow or the next day."
Wang still earned his second straight win after taking a loss or no-decision in the previous six starts. He's 5-0 in seven road starts this season and may miss time just as the Yankees moved four games over .500 for the first time this season.
"You wish for the best," Jeter said. "It's one of those things that you wish wouldn't happen, but if he's out for a while, we're going to have guys step in and fill that void."
Yankees manager Joe Girardi said he would be "shocked" if Wang made his next scheduled start, against Cincinnati on Saturday. But Girardi also wouldn't speculate on how serious the injury might be.
"We'll have the tests tomorrow and then decide what the best plan of action is," Girardi said. "You're going to go through injuries. Clubs are going to go through injuries and you've got to find a way to get it done."
Alex Rodriguez hit a three-run homer, his 185th as a Yankee, later in the New York sixth, tying Paul O'Neill for 16th on the franchise's all-time list. Rodriguez reached 1,540 RBIs on the home run, passing Joe DiMaggio and tying Willie Stargell for 40th all-time.
Roy Oswalt (5-7) gave up seven runs on eight hits and matched season highs in walks (four) and pitches (117).
The Astros have lost nine of 11 and dropped five straight home games for the first time since August 2006.
Houston was swept for the second time this season and has lost six consecutive series. "I just know we're playing bad and we've got to get better," Oswalt said. "The entire staff, we all need to step it up. I'm as much to blame as anyone."
Jorge Posada added a two-run homer and Robinson Cano a two-run single as New York won for the ninth time in 12 games. The Yankees have also won eight of their last 11 road games.
Oswalt needed 72 pitches to get through the first three innings as the Yankees took him deep in counts on almost every at-bat.
Hideki Matsui doubled with two outs in the third and Oswalt walked Rodriguez and Jason Giambi to load the bases. Oswalt then walked Posada to force in Matsui and make it 1-0.
Cano, mired in an 0-for-17 slump coming into the series, then shattered his bat on a two-run bloop down the left-field line.
The turning point in today's game," Girardi said of the hit. "Roy Oswalt had two outs in the third and we smack three runs on him. I've seen him pitch for a long time and he's a great pitcher and we put some great at-bats on him."
Wang breezed through the first five innings in 71 pitches, allowing six hits with three strikeouts and no walks. Oswalt was already over 100 before the top of the sixth, when the Yankees broke the game open.
After Posada and Cano singled, Wang bunted. Oswalt threw to third to get Posada as Wang took first. Damon singled to load the bases for Jeter, whose hit drove in Cano and the hobbling Wang.
As Wang was helped off the field, Houston manager Cecil Cooper brought in left-hander Wesley Wright to relieve Oswalt. Matsui singled to center, scoring Damon, before Rodriguez hit his 12th homer of the season to left.
Wright hit Giambi with a pitch before Posada hit his third homer of the season for an 11-0 lead. The Yankees added two more runs in the eighth off Oscar Villareal.
Houston was swept for the second time this season and has lost six consecutive series.
"I was totally embarrased by this," said Houston manager Cecil Cooper. "It won't happen again. If you don't play hard, you won't play. Simple. We're not going to settle for it anymore. Today, we didn't even show up, didn't even compete. A total embarrassment."
