"We'll get him out there and see what the need is and see what it looks like," Matheny said. "That's something everybody likes to have -- a big arm that has pitched in big situations. All season we've been trying to get right. We watched him do some pretty special things last year. That's in there. It's just helping him get there again."
Rosenthal went on the DL with a 5.13 ERA in 40 appearances. He boasted a strikeout rate of 13 per nine innings, but also had the worst walk rate (7.3) of his career.
Rosenthal, who recently acknowledged feeling arm discomfort since his first appearance of the season, threw two live batting-practice sessions within the last six days. Afterward, Matheny described Rosenthal's showing as "electric." Rosenthal was particularly encouraged by the extension he was able to get on his follow-through, which was something that eluded him earlier this year.
• Left fielder Matt Holliday (right thumb fracture) now sits in line as the next Cardinal likely to come off the DL. Holliday took ground balls in the infield Thursday and participated in batting practice. Holliday is expected to face one of the Cardinals' pitchers in a simulated game sometime over the next few days.
• Aledmys Diaz's absence from Thursday's lineup was unrelated to the right thumb injury that caused the rookie shortstop to miss 36 games, Matheny confirmed. Rather, it was a decision Matheny made after sensing that Diaz was fighting through fatigue while making consecutive starts Tuesday and Wednesday.
"You could tell his hand was fine, just the rest of the body was not quite in that consistent game-playing shape yet," Matheny said. "We'll get him a day today and then re-evaluate as we head back into [Friday]."
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.