With Williams Perez sidelined by a right elbow impingement, Collmenter could slide into the big league rotation and start Saturday's home game against the Nationals. Joel De La Cruz and Ryan Weber are also options to receive the start on Saturday.
Collmenter opened the 2015 campaign as the D-backs' Opening Day starter before moving to the bullpen after posting a 3-6 record and a 5.24 ERA through his first 12 starts. The 30-year-old found success as a reliever with a 1.89 ERA in his final 52 1/3 innings of the season.
But Collmenter couldn't replicate those numbers in 22 1/3 innings of relief this year, recording a 4.84 ERA, and was released by Arizona on Aug. 7.
Three days later, the right-hander signed a Minor League contract with the Cubs. He made four appearances with Triple-A Iowa, going 1-0 with a 2.25 ERA in 16 innings.
Wieland, meanwhile, joins the Braves after being outrighted by the Mariners and sent to Triple-A Tacoma on Aug. 20. The right-hander posted a 5.38 ERA in 22 games with Tacoma before joining the big league club on Aug. 12 . He allowed six runs across five innings against the Athletics before being optioned back to Triple-A and later outrighted off the 40-man roster.
Pat James is a reporter for MLB.com based in Atlanta. This story was not subject to the approval of Major League Baseball or its clubs.