Veras, who has made six appearances this season, said he's had some discomfort for a few days.
"I didn't pay attention to it, and then little by little, it got worse," he said. "I didn't say anything, because I didn't think it was a big deal, and I felt I could pitch like that."
He last pitched on Thursday, and gave up two runs in one inning against the D-backs. Veras was removed from the closer's job after blowing a two-run lead on April 11 against the Cardinals, and has made two appearances since then. Could this be a good time for a mental break?
"It might, sure," Renteria said. "You give yourself a little distance. He feels he hasn't done what he should be doing. Maybe it'll clear his mind a little bit, and hopefully he's feeling physically better and we can move forward."
"Maybe. Who knows?" Veras said about whether the time off will help him mentally. "At the same time, I don't want to be in a position where I can't help the team win ballgames. I want to help the team win ballgames. That's why they brought me here. Even though I'm struggling, it's just the start of the season, five or six outings, and I'm used to throwing 70 outings every year. Hopefully, I can come back, and when I come back, I can start over and healthy 100 percent."
However, obliques can be tricky and take some time to heal. Veras said he's never had this problem before, and it may have been caused by all of his side sessions.
"I have to take care of it," Veras said. "I can't pitch better if I don't get healthy."
The Cubs recalled right-hander Brian Schlitter from Triple-A Iowa. He was closing there, and could fill in as the Cubs go with matchups in save situations.
"The situation will dictate with usage of our guys," Renteria said about who he'll use as closer. "We're just glad we have a little flexibility available to us."
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.