"Obviously," manager Joe Girardi said, "Moose would be hard to replace this year."
Without Mussina, the Yankees already would have graduated from genuine worry to full-fledged concern, but with him, they still have a shot. Not only was his final line on Thursday one of his best this season, but Mussina did it against the Majors' most productive offense, in one of the league's foremost hitter's parks.
He did it in 98-degree heat, mowing down Josh Hamilton and Michael Young and Ian Kinsler, the three main engines of this Rangers offense. And he did it by pitching -- really pitching -- on a night when his stuff was self-admittedly ordinary.
"I just kept going with what I had," Mussina said. "I kept mixing it up."
He also got a little lucky -- at least from his own perspective. Mussina referred to one play in the sixth inning, when he caught Marlon Byrd in a rundown before Wilson Betemit gunned down Brandon Boggs, who was trying to reach second base in the confusion.
And though Mussina allowed Rangers to clog the bases in nearly every inning, he didn't allow a single one of them to make it home. He walked just one batter -- on a pitch that easily could have been called a strike three -- and he struck out six.
All of which left the Rangers baffled at themselves.
"We have the best offense in the league," starting pitcher Scott Feldman said. "Tonight probably would have been enough to win any other night, but not the way Mussina was pitching. He pitched an unbelievable game. We have a great offense, but he was able to shut them down."
Consider it another bit of luck that Betemit unwittingly allowed the Yankees to add an insurance run in the ninth inning, sprinting back to first base on a potential double-play ball. Kinsler didn't tag Betemit but instead threw to first, nullifying the force and giving the Rangers only one out.
Two batters later, Derek Jeter hit an RBI single.
"I've never seen that happen before in my life," Jeter said.
Jeter's offense carried the Yankees in a similar way that Mussina's pitching did -- by being timely and complete. In the lineup as a designated hitter for the first time in two years, Jeter blasted a solo homer in the first inning and finished with three hits.
That was enough to pick up Alex Rodriguez, who finished 0-for-4 and is now stuck in an 0-for-15 slump. And not that the Yankees needed it, but Johnny Damon also tacked on a run with an RBI single in the fifth.
They didn't exactly need it because Mussina was so successful -- at a most critical time. Entering Thursday's play 6 1/2 games out of first place in the American League East and entering this weekend with three games against the Angels on the horizon, the Yankees couldn't afford to lose this series to the Rangers. They just couldn't. Especially considering the uncertainty in their rotation -- Ian Kennedy and Dan Giese will pitch this weekend -- Thursday's game was as critical as any they've played in some time.
Without Mussina, it could have been a disaster. With him, it was a success.
"Moose has been big for us all year," Girardi said. "We needed a win, and Moose provided it."
Mussina now has 15 wins on the season, marking just the second time he's hit that milestone since 2003. And though he's not yet willing to consider the 20th victory that has eluded him throughout his career -- "not until I get to 19," he said -- he did stop after Thursday night's game to consider the significance of 15.
"It's ..." he said.
Then Mussina broke into a wry smile.
"I've got some more games to pitch, and hopefully, I can keep doing what I've been doing," he said. "I'm not going to try to change anything or invent something new. I'm just trying to keep going out there and preparing and doing what I've been doing."