After that rest, Rosenthal is expected to begin a throwing program.
"I think, for him, he feels pretty confident that this will help get him over that hump and then allow him to get throwing again," general manager John Mozeliak said. "We're very optimistic that by late August he should be ready to go."
The question then becomes how effective Rosenthal will be once he returns. He has fought command issues all season and lost his role as closer in late June after blowing his third save. Rosenthal hit the DL with an ERA of 5.13 and a walk rate of 7.3 per nine innings.
• Cardinals Minor Leaguer Luke Doyle, who is currently serving a 50-game suspension for testing positive for an amphetamine in March, has been handed an additional 100-game suspension for refusing to take a drug test. Doyle, a 20th-round pick in the 2015 MLB Draft, hit .207 in 44 games with Rookie-level Johnson City (Tenn.) last year.
• Though the non-waiver Trade Deadline has passed, clubs can still deal for players in August. However, the process becomes more complicated, as players must clear revocable waivers to be traded to any other team. In instances where a player is claimed off waivers, his current club can work out a trade with the claiming team or take the player back. Mozeliak said he'll keep an eye on the waiver wire for possible additions, but does not anticipate any.
"It's hard to imagine that there's something we could put a claim in and get that would make sense," Mozeliak said.
• Cardinals top prospect Alex Reyes allowed four runs on six hits and three walks over 4 1/3 innings with Triple-A Memphis on Monday. Pitch efficiency was an issue again, too, as Reyes needed 99 pitches to get that deep. Reyes' continued command issues have given the organization pause about a potential callup of the right-hander later this season.
Jenifer Langosch has covered the Cardinals for MLB.com since 2012, and previously covered the Pirates from 2007-11. Read her blog, follow her on Twitter, like her Facebook page and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.