ST. LOUIS -- Cardinals pitching prospect Marco Gonzales won't throw for about three weeks and will get a cortisone injection for a shoulder injury.

St. Louis general manager John Mozeliak said Tuesday an MRI showed the 23-year-old left-hander has an impingement. Gonzales is on the roster of Triple-A Memphis, and he skipped a start in late April.

Mozeliak says Gonzales will be re-evaluated in a week to 10 days. He also said Gonzales needs to work on strengthening exercises.

"I think it's very good news because this is something that can be managed," Mozeliak said. "There's probably a few things that he needs to start doing in his daily routine to get him through this."

Selected with the 19th overall pick in the 2013 amateur draft, Gonzales was among the spring-training contenders for the fifth starting.

Gonzales was 4-2 with a 4.19 ERA in five starts for St. Louis last year and pitched in relief in the postseason. He is 0-1 with a 6.35 ERA in six minor league starts this year.