Veras, projected at the start of the season as the Cubs' closer, had an 8.10 ERA in 12 games. Rondon replaced the veteran as the Cubs' closer before Veras went on the disabled list April 26 with a strained left oblique. The Cubs signed Veras on Dec. 27 to a one-year, $4 million deal with a club option for 2015.
"You're disappointed when you sign a free agent and bring in a veteran and it didn't work out," Chicago general manager Jed Hoyer said Tuesday. "I think he'll land on his feet."
The Cubs had hoped Veras, 33, would stabilize the bullpen, but he struggled at the start of the season, giving up 10 earned runs over 5 2/3 innings in April for a 15.88 ERA. Last year, he walked eight over 19 2/3 innings for the Tigers; this year, he walked 11 over 13 1/3 innings.
"He was throwing the ball really good the last couple outings he had," Cubs catcher Welington Castillo said. "I feel really bad for him because he's a really good person. You just wish him the best, and hopefully some team will pick him up."
Rondon was 6-for-7 in save situations with a 1.59 ERA in 22 games overall, and the Cubs have relied on young hurlers Brian Schlitter, Neil Ramirez and Justin Grimm.
"For us, when we sat down and made the decision, ultimately we have a lot of young guys playing well and competing well in important leverage situations," Hoyer said. "We want to stick with those guys right now."
The Cubs will continue to carry 13 pitchers. Most teams have 12, but manager Rick Renteria said he didn't feel short-handed, and they want to be careful with pitch counts for the young relief corps.
"We're still mindful with the younger guys and we have to watch how we use them," Renteria said.
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.