To take Zobrist's place, the Rays recalled 22-year old infield Joel Guzman from Triple-A Durham.
"I was feeling a little bit sore and took a swing," said Zobrist, describing how the injury occurred. "After that first swing I knew something wasn't right."
The 2007 season has been a struggle for Zobrist. He began the season as the team's starting shortstop before struggling and getting optioned to Durham on May 11; he was recalled on July 29.
"Yeah, it's been a tough year," Zobrist said. "I don't want to forget it, though. I don't want to have to learn the lesson twice. Whatever I needed to learn this year, I want to learn it now, that way when things come in the future I'll be more prepared."
Zobrist pointed to the area underneath his right rib cage as the location of his injury.
"The word is it takes awhile [to come back from a strained oblique]," Zobrist said. "They were saying two weeks before I can even swing a bat. I hope to get back in a couple of weeks, but if it's longer than that, [I'll] just take it in stride and don't try to push it too hard because I don't want it to happen again."
Zobrist was scheduled to have an MRI on Sunday afternoon.
Guzman batted .242 in 109 games for the Bulls, hitting 16 home runs and driving in 64 runs while playing third base and first base. His lone Major League action came in 2006, when he played in eight games for the Dodgers and hit .211 with three RBIs. Guzman was acquired from the Dodgers along with outfielder Sergio Pedroza for Julio Lugo at the trading deadline last season.
Guzman began his career as a shortstop.
"We want to get him some work at first, third and short; maybe some second," Rays manager Joe Maddon said. "I like his hands. I liked his actions in Spring Training. He's got a strong arm. He's confident about playing [shortstop]. He has to hit to be a Major League player."
Guzman believes he has improved this season while playing at Durham.
"I think I've made a lot of progress on my defense, mostly being more consistent," Guzman said.
Baldelli's week: Rocco Baldelli [left hamstring] will begin playing in games Monday as a member of the Class A Vero Beach club. Baldelli will be the DH on Monday and is scheduled to have two at-bats. The rest of his week will be as follows: Tuesday, DH, three at-bats; Wednesday, off; Thursday, center field, two at-bats and three innings; and Friday, DH, three at-bats.
Baldelli's progress will be reevaluated after Friday's game.
Knuckler next: When Tim Wakefield sees Rays green he smiles. And why shouldn't he? His career numbers against the Rays are staggering at 18-2, with a 2.83 ERA. In addition, he is 8-0 with a 2.33 ERA at Tropicana Field.
Carl Crawford is the exception among Rays players in that he has done well against Wakefield as evidenced by his .329 (23-for-70) career average against the Red Sox' knuckleballer with two home runs and eight RBIs.Crawford said he throws out conventional hitting wisdom when facing Wakefield.
"As far as staying on the inside of the ball and taking a proper swing [against Wakefield], I take more of a wild swing, like a softball swing, kind of like -- 'just try to see it and hit it,'" Crawford said.
Wakefield held the Rays to two hits over eight scoreless innings on Monday night in Boston.
"That was like the best I've ever seen him," Crawford said. "[Wakefield's knuckleball] was dropping real good. He was spotting everything good. If it's over the plate, it's easier to hit, but he was hitting the outside and inside corners."
C.C. on the run: Crawford stole his American League-leading 40th base on Friday night, a number he has reached in each of his five full Major League seasons. Only two other active players reached 40 steals in each of his first five full seasons, Kenny Lofton and Juan Pierre.
Crawford, who took the lead on July 19, is seeking to lead the AL in stolen bases for the fourth time. Only nine players have won four or more AL stolen base crowns. He also is attempting to become the sixth player to lead the AL in stolen bases four times in a five-year span, as well as attempting to become the seventh player to win four stole base titles by age 26.
Golden arm: Delmon Young has two assists thus far in the Cleveland series, giving him 13 for the season, one shy of the club rookie record (14, Baldelli in 2003). Only the Braves' Jeff Francoeur (17) and the Twins' Michael Cuddyer (16) have more among Major League outfielders. And only one rookie -- Peter Bergeron, with 16 for Montreal in 2000 -- has had more assists in the 2000s.
Up next: Scott Kazmir (9-7, 3.44) will start for the Rays in the first game of their three-game series against the Red Sox on Monday night in a 7:10 ET contest. He'll be opposed by right-hander Tim Wakefield (14-10, 4.55).
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.