"He's battling his knee, but he feels responsible to pitch," Francona said. "He's not pitching with the effectiveness he wants or we need. So I kind of took it out of his hands a little bit. I know he is shouldering a lot of responsibility and it's very difficult for him. That's why I stepped in and took this off him. He will take the ball every night and he'll do it under unbelievable circumstances, so I've got to try to help him out here."
Francona said Foulke's arm has not been affected and that his arm strength is "better than it's been."
Foulke lost a lead in the bottom of the ninth Monday, allowing two runs in a 6-5 loss to the Texas Rangers. He is 5-5 this season with a 6.23 ERA, a season after recording 32 saves and a 2.17 ERA, and allowing only one earned run in 14 innings in the playoffs.
Francona said he had "extensive talks" with Foulke, the team medical staff and general manager Theo Epstein before making the decision to have Foulke examined.
"It got to the point where I had to do something, because he'll never turn the ball down," Francona said.
"That's the kind of guy he is. I don't care what people write or say, the fact is, he'll take the ball every day, and I needed to step in and say, 'No, you won't. We're going to get you looked at.' And I think he's OK with that. I think he actually appreciated it."
Francona said he is not sure who will serve as closer in Foulke's absence, but Mike Timlin is the top candidate.
"This has sort of happened on the run," Francona said. "We want one of our main guys out there. If it's a tight game and we think we can win, we're going to use the guys we think can get outs. When you hear about bullpen by committee, you're open to failure because as a manager, there's not that concrete end in sight."
Closing in the Iron Horse: Manny Ramirez inched closer to history with his third-inning grand slam Tuesday. It was the 20th slam of his career, passing Eddie Murray for second on the all-time list. Ramirez now trails only the legendary Lou Gehrig, who hit 23.
Still streaking: For the second consecutive night, Johnny Damon got the suspense out of the way early, leading off the game with a single to extend the longest hitting streak of his career.
Tuesday's hit, a flare to left, gave Damon a 21-game streak, tying Darin Erstad of the Angels for the longest in baseball this season. Damon's streak is the longest for the Red Sox since Nomar Garciaparra hit in 26 consecutive games in 2003.
Hot hitters? The Red Sox took batting practice at Ameriquest Field's indoor batting cage Tuesday and will do so again Wednesday, a concession to the brutal North Texas heat. Francona made that decision before the team arrived, in part because he remembered what it was like in his days as a Rangers coach.
"As the home team, we would have extra [batting practice] from 3-4," Francona said. "God bless [Rangers hitting coach] Rudy Jaramillo, I love him. But I wanted to kill him. We would stand out in the outfield and shag. It would be a thousand degrees, and we'd walk after a ball, go pick it up, and we ... [complained] for an hour. Finally, we were hitting too many balls out of the ballpark, so I volunteered to go sit in the stands and collect the home run balls, so I could sit in the shade.
"When I'd get home at night ... I remember getting in the shower, thinking, 'I don't have the energy to get out of the shower.' It gets you. It's hot. And it doesn't go away. You'd see visiting teams look up at those boards and see 104, and you'd see them wilting. I want our best energy to be during the nine innings. I don't want to leave it out there during BP."
Still, not all the Red Sox mind the heat.
"I love it," Damon said. "You get to go out there and sweat off all that extra food you tend to eat. To me, it makes you feel alive. In Boston, it can drop down to 58 degrees any day."
Indeed, on Monday, the temperature in the second inning was announced at 96 degrees, and the announcer noted that it was 69 in Boston. Tuesday, however, the game-time temperature was a relatively mild 91.
Short hops: David Ortiz hit the 150th home run of his career in the first inning, a 416-foot drive to center field. ... Tim Wakefield's start was the 300th of his career. ... Wade Miller's starts have a familiar look to them. Monday marked his fourth consecutive no-decision, all in games decided in a team's final at-bat. ... The Red Sox entered Tuesday's game having not played an extra-inning game this season. The string of 81 games to start a season is a Major League record, breaking the mark of 69 set by the 2002 White Sox.
On deck: Matt Clement will look for double-digit wins when he faces Chan Ho Park in the finale of the three-game series on Wednesday night at 8:05 p.m. ET.