Lester is scheduled to start against the Yankees on Saturday afternoon at Yankee Stadium in the second of a three-game series between the American League East rivals. New York took the opener Friday, 10-3, to improve to 6-1 against Boston this season.
The Sox's Opening Day starter has not been himself in 2012 with a 5-8 record and a 5.46 ERA. To make matters worse, the Red Sox are 7-13 with Lester on the hill.
While the Sox continue to look for starting pitching help with the non-waiver Trade Deadline on Tuesday, the best thing for the club would be for Lester to return to form as the team's ace.
"That's more important than any trade we can make," said Boston general manager Ben Cherington. "We need to help him. He's gone through a rough patch and we've ... had core players go through rough patches in the past. We're at our best when we circle around those guys, helping them get through their rough patch. That's what we got to do now. We know how good he is, and he's feeling good about how important he is to the team."
Lester's "rough patch" includes a 0-3 mark and 10.42 ERA in four July starts. The left-hander had arguably the worst outing of his career his last time out, giving up a career-high 11 runs on nine hits and a surrendering a career-worst four home runs against the Blue Jays at Fenway Park in four-plus innings.
"Obviously it's embarrassing," said Lester, who will make his second start against New York this season. "I've let my team down a lot this year. It's hard for me to walk around this clubhouse and look guys in the eye right now. I'm not pitching well. I'm not doing my job."
The Red Sox enter Saturday's game two-games below .500 at 49-51. It's the first time Boston has been two games under the break-even mark since it was 31-33 on June 15. But that doesn't mean the Yankees (60-39) are taking their bitter rivals lightly.
"They've had a lot of injuries like we have," said New York manager Joe Girardi. "The important thing is what happens in the next 64, 65 games, not really what's happened up until this point. That's the way we look at it, too. And I'm sure that's the way they're looking at it. Can they make a run and get hot? And our thought is, can we get hot again and distance ourselves from the other teams."
The Yankees will send CC Sabathia to the mound as they look to continue their recent dominance over the Sox. New York is 9-2 in the last 11 meetings and 11-5 against Boston since Aug. 5, 2011.
In two starts since a brief stint on the DL, the left-hander has allowed just three runs in 13 innings with 12 strikeouts. Sabathia will face the Red Sox for the first time this year.
Red Sox: Ortiz sheds walking boot
Red Sox slugger David Ortiz took batting practice on Friday at Yankee Stadium and did not wear a walking boot as he continues to progress from a right Achilles strain.
Ortiz missed his 10th game on Friday since going on the 15-day disabled list. The Red Sox are hopeful their designated hitter will return to the lineup on Wednesday, the first day he is eligible.
"I think he's on pace to back when his [DL] stint is over," said manager Bobby Valentine.
Ortiz rejoined the team Friday after staying back in Boston for the Texas series. The club's leading hitter is taking a wait-and-see approach with his injury.
"I don't know. Every day is different," Ortiz said. "Every day for me it has been improving. We'll see. If I'm ready to go, I'm ready to go. I want to play."
The Red Sox have struggled to score runs with Ortiz sidelined, going 3-7 without him.
"It's hard to tell," said Valentine. "We've faced some good pitching and it's hard to tell. You know, David was so on since Day 1 of the season that it's hard to say you haven't missed him. He's pretty good."
Jarrod Saltalamacchia hit his 20th home run of the season on Friday, a solo shot in the fourth inning. He leads all Major League catchers in home runs and is on pace for 31.
Carlton Fisk holds Boston's all-time record for home runs by a catcher with 26 in both 1973 and 1977.
Saltalamacchia has gone deep in nine of his last 28 games since June 16. He finished Friday's loss 1-for-4 with three strikeouts.
Yankees: Swisher close to return
Nick Swisher took batting practice and ran the bases before Friday's game and and Girardi said the outfielder could return to action as soon as Saturday.
"I think a lot of it depends on how he feels [on Saturday]," Girardi said Friday.
Swisher has not played July 20, the result of a mild left hip flexor. The Yankees are being cautious with the right fielder and don't want to rush him back to avoid the possibility of a setback.
"We're making sure he's as close to 100 percent as possible," Girardi said. "When you have slight strains, you have to make sure that you don't necessarily have a setback."
Swisher will play in right field when he returns, with newly-acquired Ichiro Suzuki moving into left field.
Joba Chamberlain threw a bullpen session on Friday at Yankee Stadium and is scheduled to make his next Minor League rehabilitation appearance on Sunday with Double-A Trenton.
The reliever said he has been clocked between 94 and 100 mph in his previous rehab outings and is closing in on a return to the big league club.
"I never had any doubt whatsoever," Chamberlain said. "Obviously the surgery is only a third of it; the rehab is two-thirds. I've never been one to shy away from hard work and prove people wrong. It's going to be awesome to put this uniform on again and pitch for this team."
The right-hander is recovering from Tommy John surgery performed last June and an open dislocation of his right ankle suffered this spring. The 26-year-old has allowed one earned run and three hits over eight Minor League innings spanning six games -- three with the Gulf Coast Yankees and three with Class A Tampa. Chamberlain has seven strikeouts against one walk.
"I got challenged every day," he said. "They never gave me more than two weeks in advance, because they knew if they gave me more, I'd probably try to skip a week. I know how my body is; I know how to push myself. My ankle is strong, and I've got to continue to work and not let up on anything we've done to this point."
The Red Sox have lost seven of their last 10 road games and are 24-23 away from home this season.
New York has outscored Boston, 18-9, in the first inning this year.
Yankees shortstop Derek Jeter is 19-for-52 (.365) in his career against Lester with one homer and five RBIs.