Roberts has ruptured tendon

Orioles second baseman Brian Roberts suffered a ruptured tendon behind his right knee yesterday while stealing second base at Tropicana Field, and he's expected to miss two to four weeks of the season. Roberts underwent an MRI on his knee this morning in Baltimore, and team orthopedist Dr. John Wilckens passed along the results to Orioles officials. Roberts had to be carried off the field in the ninth inning yesterday after hearing a popping sound behind the knee. The Orioles officially placed Roberts on the 15-day disabled list with a "right hamstring strain" and recalled infielder Yamaico Navarro, 25, who was acquired in a Nov. 30 trade with the Pittsburgh Pirates for minor league pitcher Jhondaniel Medina. Navarro already is on the 40-man roster - a fact I overlooked earlier today - so space doesn't need to be cleared. Wilson Betemit won't be transferred to the 60-day disabled list. Navarro hit .276/.417/.379 in 29 spring training at-bats for the Orioles after hitting .279/.366/.491 in 66 games with Triple-A Indianapolis last season and going 8-for-50 with the Pirates. He will wear No. 54. Ryan Flaherty is starting at second base today, and the Orioles also have Alexi Casilla on the bench. Roberts has played in 115 games over the past three seasons because of a herniated disc in his back, concussion symptoms and a torn labrum in his hip. He underwent surgery in December for a sports hernia. Roberts has returned to Camden Yards today, but he isn't available to the media. Surgery isn't being considered at this time. The tendon often is used to replace torn ligaments, so it isn't needed for Roberts to resume playing.