BOSTON -- The Yankees had their trying times and survived. Now, with two months to go in the season, the Red Sox have theirs.

As Gary Sheffield and Hideki Matsui enter the final round of rehab and work toward a return to the lineup, the Yankees sit percentage points in front of the Red Sox in the American League East standings.

Some projected that, minus two 100 RBI hitters in their everyday lineup, the Yanks would eventually drift out of contention. Instead, the Yankees hung with the Red Sox throughout the middle third of the schedule, refusing to go away.

Just as the Yankees are getting healthy, the Red Sox are succumbing to injuries. On Sunday night, Trot Nixon left the game with a strained biceps muscle that will sideline him for the rest of the month.

Yesterday, after a battery of tests, it was determined that Jason Varitek was suffering from a torn meniscus, requiring arthroscopic surgery. He also will be lost until September.

In the span of two days, the Red Sox lost two regular position players. How well the Sox respond to their absence will go a long way in determining whether they reach the postseason for the fourth consecutive season.

Nixon's injury is likely to take a lesser toll, at least offensively, since Wily Mo Pena can supply as much, if not more power than Nixon. In Fenway's spacious right field, Pena could be an adventure, but he has the athleticism to cover ground and his arm is superior to Nixon's.

Having Pena in the everyday lineup, of course, will thin the club's depth. Currently, Gabe Kapler is the only other outfielder on the roster.

Varitek, meanwhile, will be sorely missed, even if he was hitting just .243. His true value comes behind the plate, where his instincts and exhaustive preparation guide pitchers. That's never been more valuable than this season when the Sox have, at times, carried as many as five rookie pitchers at once.

Two years ago, backup Doug Mirabelli would have been a suitable short-term replacement. But Mirabelli's bat has been anemic this season -- .188 before last night. Aside from his singular gift of handling Tim Wakefield's knuckler, his catching has dipped, too.

The timing of the injuries couldn't be worse, coming as they did immediately before the trade deadline (Nixon) and hours after (Varitek). It will be especially problematic to find replacement parts, since any players obtained in trades must now first clear waivers.

Injuries aren't the only problem with the Sox; just the most obvious.

The club's pitching -- both at the back of the rotation and the middle-to-back of the bullpen -- remains suspect. Jason Johnson's emergency start last night (5 2/3 innings, three earned runs allowed) was at least passable. But the fifth spot has been a veritable revolving door for the better part of the season, and the recent loss of Wakefield has reduced the rotation further.

As currently constituted, the Sox are relying on Jon Lester, with all of 56 2/3 innings of major league experience, as their No. 3 starter.

In relief, Craig Hansen and Manny Delcarmen are suffering from growing pains. Hansen has allowed four runs in his last two appearances and Delcarmen, hampered by a nagging thumb injury, has been shelled for eight hits and five runs in his last 2 1/3 innings. Both are talented, but still relatively inexperienced and there's little margin for error in a pennant race.

There exists no other options in the pen, as the Red Sox long ago consigned Julian Tavarez and Rudy Seanez to games in which the Sox either lead safely or trail hopelessly.

Help isn't on the way. That door slammed shut Monday afternoon. The Sox, correctly, aimed high and otherwise refused to sacrifice their young arms for short-term gain.

But that means they'll have to dig themselves out of their current mess. They'll have to overcome their injuries, get contributions from unexpected sources and remain in contention.

In other words, they'll have to do exactly what the Yankees have been doing for the last three months.

smcadam@projo.com / (401) 277-7340