Two of Major League Baseball's bigger disappointments square off on Tuesday when the Boston Red Sox and the Los Angeles Angels of Anaheim start a three-game series at Fenway Park.

Boston enters this series four games under .500 and in fourth place in the American League East, 13 games back of the New York Yankees. The Red Sox still have a pulse, albeit, a small one in the wild card race, as they sit seven games back of the final spot.

But, if the Red Sox are going to make a late season run here they will have to do so without outfielder Carl Crawford, who will miss the remainder of the season to have Tommy John surgery to repair the torn ulnar collateral ligament in his left elbow.

"Carl Crawford has a chronic left elbow ulnar collateral ligament tear," the Red Sox said in a statement Monday. "While he has been following a conservative treatment protocol and playing with this injury, his symptoms are getting worse. After consultation with the Boston Red Sox medical staff and with Dr. James Andrews, the decision has been made to proceed with a left elbow ulnar collateral ligament reconstruction (Tommy John surgery). The surgery will be performed by Dr. Andrews on Thursday, Aug. 23. We expect Carl to make a full recovery."

Then, as if that wasn't enough, the Red Sox relieved pitching Bob McClure of his duties. McClure had butted heads with manager Bobby Valentine all season to the point that the two rarely even spoke anymore.

'This decision didn't have anything to do with that. We felt like we needed to make a change to put our pitchers in the best position to do what they needed to do in the next six weeks," Red Sox general manager Ben Cherington said. "The next six weeks are important no matter what our record ends up."

On Tuesday, Boston turns to righty Aaron Cook, who has lost five of his last six decisions. Cook lost in Baltimore on Wednesday, as he allowed five runs (2 earned) and three hits in 5 1/3 innings. He also walked three in the loss and fell to 3-6 on the year to go along with a 4.58 ERA.

Cook actually carried a no-hitter into the sixth inning of that one, but his own throwing error led to five runs.

"I let the team down. We're trying to win games, and that was a game we should have won," Cook said. "It's a play I've made 100 times. I just didn't get my feet set."

Cook has faced the Angels three times and is 2-1 against them with a 2.86 ERA.

The Angels, meanwhile, have lost 13 of their last 18 games and have slipped 9 1/2 games back of the Texas Rangers in the AL West, but are only four games behind in the wild card chase.

"I don't want to be redundant, but the season's still in front of us," Angels manager Mike Scioscia said. "We're going to have our opportunities if we get our team where we need it to be, and that's what we need to focus on."

The Angels will rely on righty Ervin Santana in Tuesday's opener. Santana beat the Cleveland Indians on Wednesday, holding them to a run and four hits in seven innings, as he ran his record to 6-10, while lowering his ERA to a still lofty 5.59.

"I know that I hadn't been pitching good, but I was just doing my best, and I just think positive every time," Santana said after the game. "The last few outings I had been getting better, and then tonight, even better."

Santana is just 2-3 lifetime against the Red Sox with a 4.27 ERA in 10 starts.

Boston took six of eight meetings with the Angels last season.