David Wells went on the disabled list for the second time this season Saturday, another blow to the Red Sox rotation after they opened spring training with seven pitchers competing for five starting spots.
That group is down to four with the trade of Bronson Arroyo to Cincinnati and the success of Jonathan Papelbon as the closer. So Lenny DiNardo, who has one start in 30 major league games, probably will fill in for Wells on Monday against Seattle.
Boston replaced the left-handed Wells on the roster with right-handed long reliever Jermaine Van Buren, who was called up from Triple-A Pawtucket.
The Red Sox said Wells has a sprained right knee, which underwent offseason surgery. He received a shot of the joint lubricant Synvisc after Friday night's win over Seattle. That usually is administered in a series of three injections a week apart. Wells was placed on the 15-day disabled list retroactive to Thursday, meaning he can't be activated before April 28.
He said he was hurt when he ran to cover first base in his only start this season Wednesday night.
"When you have a bad knee, anything can happen at any given time," Wells said. "It's been tender. There's been good days and bad days."
Manager Terry Francona and general manager Theo Epstein refused to put a timetable on Wells' return. Meanwhile, Curt Schilling, Tim Wakefield, Josh Beckett and Matt Clement are the top four starters.
The 42-year-old Wells began his 20th major league season on the disabled list and struggled in a rehabilitation start April 7 at Pawtucket. He struggled again in his first start of the year for Boston last Wednesday in an 8-4 loss to Toronto, allowing seven runs on 10 hits — three of them homers — before leaving with no outs in the fifth.
"I'm going into this with very positive, good thoughts," he said. "A lot of people have been in this situation and come back and been able to pitch."
CASEY OUT TWO MONTHS: First baseman Sean Casey will be out of the Pittsburgh Pirates' lineup for six to eight weeks with two fractures in his left lower back. Casey, the Pirates' highest-paid player, was injured during Friday night's game against the Cubs while he was stretching for a throw. As John Mabry was running out an infield single in the third inning, he stumbled crossing the bag and clipped Casey with his hip or left elbow. Casey took several strides toward the pitcher's mound with the ball before dropping to his knees in obvious pain. He was assisted off the field and needed help getting to the clubhouse before being taken to a hospital for tests.
EDMONDS AILING: St. Louis Cardinals center fielder Jim Edmonds, who has struggled offensively and defensively in the early season, was out of the lineup for Saturday's game against the Cincinnati Reds after receiving a cortisone shot for an aching right shoulder. Manager Tony La Russa said the shot was administered after Friday night's 1-0 loss. Edmonds was batting .158 with one homer and seven RBIs and has committed three errors in the last two games after totaling two all last season.
ALSO: The New York Yankees signed infielder Carlos Pena and right-hander Jesus Colome to minor league deals . . . The Chicago Cubs sent right-handed reliever Michael Wuertz to Triple-A Iowa following a bad outing in Pittsburgh.