The 23-year-old Perez felt discomfort in his elbow in his most start last Saturday. An examination revealed inflammation, and he said this week he's leaning toward having the procedure done.
Perez is 4-3 with a 4.38 earned-run average in eight starts after going 10-6 as a rookie. He's 0-3 with a 13.15 ERA following consecutive shutouts.
The Rangers lost left-handed starter Matt Harrison this week because of a recurring back injury that forced him to miss most of last season. The 28-year-old Harrison hasn't decided to undergo another back operation, one that would fuse disks together. Harrison is likely lost for the season regardless of his decision. He's 1-1 with a 4.15 ERA in four starts.
The Rangers went into Friday night's home game against Toronto having lost four of their last five games to drop below .500 for the first time since mid-April. Amid the latest serious injuries to their starting rotation, Texas' typically potent hitting attack ranks ninth in the American League in home batting average (.258) and 12th in home slugging percentage (.380).
Manager Ron Washington said the prospect of losing Perez for the season and Harrison possibly for good won't affect how his team goes about its business.
''These guys are pros,'' Washington said. ''We've got to put 25 guys out there, and we've got to go play baseball. I think if you start trying to create a mental effect, that creates an excuse.
''Now, human nature? Yes, you think about it.''
Harrison was Texas' Pitcher of the Year in 2012 with an 18-11 record and then was limited in 2013 to two early starts before being shut down for two back surgeries. He finally made his first appearance of 2014 on April 27 but left his start Tuesday in Houston in the second inning because of back stiffness.
Harrison said he's scheduled to receive an epidural Monday to relieve pain and is fighting the reality that he might have pitched for the last time.
''I'm trying to stay positive as much as I can and take it day to day,'' he said, ''but I obviously can't go out there and pitch the way I was last time with this stuff going on.''