PHILADELPHIA — The Philadelphia Phillies have scratched right-hander Aaron Nola from his scheduled start Wednesday night and placed him on the 15-day disabled list with a strained elbow.

Right-hander Phil Klein, who is 0-1 with a 5.19 ERA in eight relief appearances for the Texas Rangers this season, will instead start Game 2 of the three-game series against the San Francisco Giants.

Nola (6-9, 4.78) said he felt discomfort after his most recent start on Thursday in Atlanta.

"But I really didn't think it was anything," Nola said. "It just kind of got sore a little bit. It kind of prolonged for the next couple of days and I told the (Phillies staff)."

The 23-year-old has been struggling for nearly two months and has a 9.82 ERA in his last eight starts. The Phillies skipped him once in the rotation before the All-Star break, but Nola said his struggles have had nothing to do with his health.

"No, no, I never felt any pain or any soreness," he said. "I guess it just kind of flared up in that one game."

Nola hopes to return this season, though the Phillies could be cautious with a young pitcher who is considered one of their key cornerstones in their rebuild.

"I'm definitely going to do everything to get back and recover from this," Nola said. "I really hope I'll be back before the end of the year."

He said he won't throw for at least a week before being re-evaluated.

In his place, the Phillies turned to Klein to face right-hander Johnny Cueto (13-3, 2.63).

A 30th-round selection in 2011 by the Rangers, Klein is 2-3 with a 4.80 ERA in 36 career games, two of them starts. The Phillies claimed the 6-foot-7, 255-pounder from Texas on June 19, and he was 1-1 with a 2.13 ERA in eight games with Triple-A Lehigh Valley before being called up.