After having an MRI today, Joe Kelly was placed on the 15-day disabled list with a strained left hamstring. In addition, Keith Butler was optioned to Triple-A Memphis.

Taking their places on the Cardinals roster: Eric Fornataro and Jorge Rondon, both rookie right-handers who are being called up from Memphis.

Kelly injured his hamstring while running to first base during yesterday’s game in Milwaukee.

Butler had made two appearances this season, allowing six earned runs in two total innings.

Here’s more on Fornataro and Rondon from Cardinals.com:

Fornataro, 26, appeared in four games for Memphis this season, going 1-0 with the team’s lone save. He had yet to allow a run and had been touched for just one hit in five innings of work. The 6-foot-1, 225-pound Fornataro was the Cardinals’ sixth-round selection in the 2006 First-Year Player Draft out of Miami Dade Community College. He has made 180 career Minor League appearances (71 starts) and will make his Major League debut with his first appearance.

Rondon, 26, was an international free-agent signing by the Cardinals in July 2006 and is a product of the Cardinals’ former Venezuelan Summer League team. The 6-foot-1, 215-pound Rondon led the Memphis squad with 51 relief appearances in 2013. He appeared in five games for Memphis this season, allowing three runs infive innings pitched. Like Fornataro, he too will be making his Major League debut with his first appearance.

Both will be in Washington, D.C., for tonight’s Cardinals-Nationals game.