Nelson Cruz expected out 3 weeks

Texas Rangers outfielder Nelson Cruz is expected to miss three weeks after an MRI on Monday revealed a Grade I strain of his left hamstring.

Cruz will receive a PRP injection from Rangers physician Dr. Keith Meister to stimulate the healing process.

Cruz injured the hamstring as he rounded first base on a double to lead off the sixth inning. Cruz pulled up a few steps past the first-base bag and grimaced. He was taken out of the game and went to the clubhouse for treatment.

Leonys Martin is the likely internal replacement for Cruz. Martin has hit .263 with no homers and 17 RBIs in 40 games (175 at-bats) for Triple-A Round Rock. He has hit a combined .295 with 19 stolen bases (and has been caught 11 times) in Arizona, Frisco and Round Rock this season. The 23-year-old signed a five-year deal worth $15.5 million with a $5 million signing bonus in May.

General manager Jon Daniels said Monday that he sees this as an opportunity to see what Martin can do for the Rangers.

"We feel Leonys has the ability to fill a role, but let's see how it plays out," Daniels said. "He's talented, though not a finished product, and the time up here can only help."

Cruz had three separate stints on the disabled list last season with hamstring strains, two of them on the left side. He missed 51 games because of them. He was on the DL for a few weeks in May of this season with a strained right quadriceps muscle.

Cruz is hitting .270 with 28 homers and 84 RBIs this season. He's leading the club in homers and is second in RBIs.

Cruz knows all about hamstring strains. In 2010, he strained his right one in April, the left in May and then aggravated his left in mid-August. He spent time this offseason working on his running style and any kind of strength and conditioning drills he could do to guard against more leg injuries.

The Rangers are hoping for some good news on the injury front this week as Adrian Beltre begins a rehab assignment for Triple-A Round Rock on Monday night. They will be in Omaha. Beltre has been on the disabled list since July 23 with a left hamstring strain. He aggravated the injury rounding first base during a running session on Aug. 6. It will be his first rehab assignment since 2001.

Richard Durrett covers the Rangers for ESPNDallas.com.