Capuano, who originally hit the DL on May 26, experienced a setback when throwing a simulated game June 17. The left-hander felt "a little bit of instability" when throwing to batters in Los Angeles during the Crew's recent road trip.
"It basically sets us back to square one where I'm not throwing right now until I'm absolutely symptom-free and I have no pain in that area," Capuano said. "Then we will do a slow progression again starting with plyometrics and leading into throwing, bullpens, sim games.
"Unfortunately it is just taking a lot of time. That's the frustrating part. Hopefully once we get the flexor strain healed up, I won't have that painful sensation again."
The news from the MRI could have been worse for Capuano, who has undergone two Tommy John surgeries. According to Capuano, the results showed a light spot in his flexor between the humerus and ulna -- likely to be bleeding caused by the strain.
"Whether that bleeding or light spot was a result of the injury or if I reaggravated it when I threw to the hitters in L.A., I'm not sure," Capuano said. "But there definitely is evidence of a strain there."
Santana returned from a stint on the DL with a right shoulder strain June 3, but only played four games before the current elbow injury sidelined him.
"He's making progress. He's not at the point of doing baseball stuff right now, though," Brewers manager Craig Counsell said. "So it's going a little slower than we'd like. He's going to be a ways away still. ... The All-Star break would be optimistic for me right now, that's what I'd say."
In Santana's place in right field has often been Ramon Flores, whose bat is beginning to come around for the Crew. Entering Friday, Flores had started in 10 games since June 8 -- the day Santana exited the lineup -- and batted .306 with a .357 on-base percentage in June with a reduced proclivity for striking out.
With Capuano's absence, the Brewers have continued to employ an eight-man bullpen.
Curt Hogg is a reporter for MLB.com based in Milwaukee.. This story was not subject to the approval of Major League Baseball or its clubs.