OAKLAND -- As if the Red Sox' lineup wasn't weak enough already.

But last night, about a half-hour before Boston was to play the Oakland Athletics, the Red Sox had to scratch MVP candidate David Ortiz because of the stomach flu that has been going through the team.

Ortiz's absence forced manager Terry Francona to do even more lineup-juggling. He moved Alex Cora up from ninth in the batting order to second, dropped Mark Loretta (sore right quad) from second to third and inserted him in the DH spot, and added Dustin Pedroia to the lineup, batting ninth and playing second base.

That left the Red Sox with a three-four punch of Loretta and Kevin Youkilis , hardly the murderer's row that generally has featured Ortiz and Manny Ramirez (right knee tendinitis).

Lester placed on DL

Promising rookie left-hander Jon Lester was placed on the 15-day disabled list yesterday because of problems with his lower back.

Lester was sent back to Boston for more tests. Francona did not think that Lester would have to be shut down for the season, but the organization was going to carefully monitor his innings and fatigue factor anyway because he's one of the cornerstones for the future rotation.

"He's going to miss a start," Francona said. "Then we get into September (when rosters expand). We just think it's in his best interests to do this (put him on the DL). If we have to shut him down we would. He's a very big part of our future. We've asked a lot of him. We don't want to hurt this kid for the future. He's too valuable."

Lester almost didn't make his last start, in Anaheim on Aug. 23, because of lower back stiffness. Lester said that night his car had been involved in a fender-bender on Storrow Drive in Boston prior to his start against New York at home on Aug. 18.

Lester has had issues with high pitch counts, forcing him out of games early, but he is 7-2 with a 4.76 earned-run average in 15 starts since his June 10 promotion from Pawtucket.

Ramirez not ready to go

Ramirez was not in the starting lineup last night for the second straight game, and Francona said that Ramirez, "at best," wouldn't be back in left field until the start of a homestand, Thursday night against Toronto.

Francona also made it sound as if he wasn't expecting to call on Ramirez for any pinch-hitting duty, either.

"I bet he could (hit), but if he runs to first base and aggravates it, then we've rested him for three or four days and then he has a setback," said Francona. "And then what if he has to slide, which he couldn't do (Saturday) night (in Seattle). He says he's fine but he can't run. When he swings the bat he has to be running."

Francona said no further tests are planned for Ramirez's knee. "He had tests (in Anaheim). We know what's wrong," he said.

Beckett an unknown

The Red Sox were expecting Josh Beckett to take the ball for his start tonight, but they have no clue how long he'd be able to go.

Beckett had to come out of his previous start because of a cut on the middle finger of his right hand. He was able to spin some breaking balls in a throwing session Sunday in Seattle, but the stress of a game would require him to put more pressure on that finger on the seams to throw a good, tight breaking ball, and no one knew how the finger would react to that extra pressure.

It's possible the Sox will have to call up another pitcher just to have available, especially after making a position-player-for-pitcher swap yesterday (Carlos Pena for Lester), given Beckett's uncertain status and the unknown factor of how deep and early Boston would have to go to its bullpen last night with rookie Kason Gabbard making his second big-league start.

Nixon, Varitek nearly ready

Catcher Jason Varitek and outfielder Trot Nixon are nearing returns to active duty, but for whom, and how soon, is the question.

Francona said that when the team gets home for Thursday's game, Varitek (knee) and Nixon (biceps) will be ready to play, but it's likely the Red Sox will want Varitek to catch maybe four or five innings in at least one game on a minor-league rehab assignment to see how his surgically repaired knee will hold up.

And Francona also said that Nixon likely needs some rehab at-bats before being able to rejoin Boston, despite the temptation to rush the two starters back into the struggling lineup.

More from the injury report

Tim Wakefield threw off the mound in a simulated-innings type of workout yesterday and appears to be nearing the form and strength he needs to reach before rejoining Boston's rotation.

Doug Mirabelli (sore left ankle) was out of the lineup, forcing Francona to start Javy Lopez behind the plate again. Mirabelli is expected to start tonight. Wily Mo Pena was going to have his sore left wrist examined by Oakland's medical staff yesterday. Snyder, who persevered in Sunday's start despite having caught the stomach flu from Youkilis, was sent home from the park early yesterday because of the illness.

Pedroia is among friends

Pedroia had a homecoming of sorts last night.

Pedroia grew up in Woodland, Calif., about a 70-minute drive from the Oakland Coliseum. He expected to have about 50 family members and friends at last night's game.

"I can remember being in junior high and high school coming to games here when they had $1 hot dog nights. It was sort of weird coming in today," said Pedroia, who is batting .111 (2-for-18) in his first five big-league games.

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