ARLINGTON -- Rangers hitting coach Rudy Jaramillo said he "blew out" his left knee while working out in a swimming pool Friday morning.

Jaramillo has been bothered by the knee for most of the season and is going to need knee replacement surgery at some point in the future. Right now, he is getting around on crutches while having to endure some serious throbbing in his knee.

"I'll get by," Jaramillo said. "This is not going to change my preparation. I'll still be able to work with the hitters, do their drills, get them ready for the other pitcher."

Jaramillo won't be able to throw batting practice, but he is able to do other things. One drill done in the batting cage is him sitting in a chair behind a screen and throwing hard underhand pitches to a hitter standing no more than 30 feet away. That allows the hitter to work on his quick hands and reaction.

Jaramillo will be able to throw batting practice once he has the knee replacement surgery, but he has talked to Dr. Keith Meister about postponing it until the end of the season.

"I hope so," Jaramillo said. "We'll just wait and see how it goes. Hopefully, I can manipulate it in my mind somehow."

Jaramillo is in his 14th season as Texas' hitting coach. The Rangers went into Friday's game with the Phillies leading the American League in runs scored and were second in hitting.