After losing two of three to the Yankees, the Sox got lit up in two of three games against the Rangers. Then, yesterday, Josh Beckett — who had struck out six, walked only one and allowed no runs — was forced to leave in the fourth inning with an ankle injury. The Sox were then forced to burn their bullpen before losing in the eleventh inning to a walk-off home run by Brett Lawrie. The Sox are on a 2-7 skid and the last loss could loom large in more ways than one.

Not only was yesterday’s loss tough to swallow, but the injury to Beckett’s ankle could affect not only the chances of winning the division, but advancing in the playoffs as well.

While there has been no official word on the severity of the ankle injury, let’s just say that it doesn’t look good.

The injury is to Beckett’s right ankle, which is a part of his push-off leg. That leg provides a good amount of the power behind his pitches, especially his mid-90s fastball. Even if it’s just a minor sprain, it will certainly take time to heal. There is also a chance that he could re-injure the ankle if he tries to push too hard upon his return. If it’s more than just a minor sprain, the Sox may have to head into October without their most valuable pitcher of 2011.

The other problem is the lack of options for his replacement. The trade deadline has come and gone and even if the Sox were to acquire an arm through a waiver trade, that player would not be eligible to be on the postseason roster. We’ve seen arms like Alfredo Aceves, Andrew Miller and Tim Wakefield fill in at times throughout the season, but none are capable of performing at Beckett’s level, or even close to it — not that many pitchers in baseball could either.

Erik Bedard’s knee injury isn’t serious, but he will miss his next start, leaving Jon Lester and John Lackey as the only two healthy pitchers out of Boston’s original five starters. One could argue that Lackey may not really count anyway.

The Sox certainly have the type of offense that could out-slug their opponents in October, but pitching seems to win more often than not in the postseason. Then again, none of the other American League teams likely headed for the postseason have a lot of shut-down depth in their rotations, unless the Angels manage to overtake the Rangers out west. Every team has an ace (CC Sabathia, Justin Verlander, C.J. Wilson and Jon Lester), but, outside of Anaheim, there is no Lincecum, Cain, Bumgarner type of rotation depth for the postseason contenders. One could make a solid argument for the Verlander/Fister tandem, however.

Obviously, Beckett’s ankle injury changes the course of the rest of the season. It doesn’t end the team’s chances of going deep into October, but if the injury is serious, it certainly hurts. Simply put, someone or a collection of someones will have to step-up in a big way, especially if Beckett can’t return before the playoffs.