Beckett, who left his last start Tuesday with back spasms, is up in the air. If he misses time, that conceivably could put even more responsibility on the shoulders of Lester, the scheduled starter Thursday for the opener of a four-game series against the Twins at Fenway Park.
The Red Sox enter Thursday having had a four-game win streak snapped by the Tigers in Wednesday's series finale, while Minnesota lost its last two games, both one-run affairs against the White Sox. The Twins, who will start streaking right-hander Sam Deduno on Thursday, had won four straight prior to those defeats.
Lester's last win came on June 27. He took three straight losses leading into his last start on Saturday, which, while certainly imperfect, was an improvement. The left-hander gave up four runs in six innings to the Yankees and took a no-decision in Boston's 8-6 win.
"Well, we need to pitch well and they know that," Boston general manager Ben Cherington said. "We pitched pretty well here the last few days, so we'll hope that continues. They know what they need to do. They've heard it a lot, but they don't need to hear it. They know that we need those guys pitching effectively and helping us win games."
Lester's July ERA in five starts was 9.36. He was a winner against Minnesota in April, with seven innings of five-run ball.
Deduno, 29, has two straight wins and a 3.13 ERA in four starts for the Twins this season. He's never faced the Red Sox after spending the first two years of his big league career -- 2010-11 -- in the National League with the Rockies and Padres.
Twins: Gardenhire wants to get Butera time
• Drew Butera was Francisco Liriano's personal catcher until the left-hander was traded to Chicago. Now, manager Ron Gardenhire has to work Butera in on days Joe Mauer could use a break.
"I don't have to line him up with anybody," Gardenhire said of Butera. "We'll get him in a game pretty quick. He needs to catch. It'll give me a chance to mix Drew in. I know fans like to see Joe Mauer play every day, but there will be a time on this road trip where I'm going to give Joe a day off."
• The Twins are 18-19 in one-run games this season.
Red Sox: Ryan Lavarnway returns to Majors
• Ryan Lavarnway was recalled from Triple-A Pawtucket on Wednesday. He made his Major League debut late last year, helping the Red Sox to a victory in the second-to-last game of the year with a pair of home runs.
The Sox already have two catchers -- Jarrod Saltalamacchia and Kelly Shoppach -- but need Lavarnway's bat with designated hitter David Ortiz out. Lavarnway was hitting .295 with eight home runs at Pawtucket.
"This has been my first opportunity to catch on an everyday basis," said Lavarnway, who's been the starter for Pawtucket. "I've got to tell you -- it's a lot different than DHing half the time. It's more of a physical grind. I think I've already caught 20 more games than I've ever caught in a year. But I've got a great postgame routine. I'm staying in shape a lot better this year, working on my flexibility and my body feels great."
First baseman Adrian Gonzalez had two hits in Wednesday's game, his 17th multihit game in his last 33. He is hitting .389 (51-for-131), tops in the American League in that time.