John Lackey (shoulder), Hector Rondon (triceps) to go on 15-day DL

DENVER -- The Chicago Cubs will place right-handers John Lackey and Hector Rondon on the 15-day disabled list Friday and recall rookie pitchers Rob Zastryzny and Felix Pena, a source told ESPN.

Lackey has been dealing with a sore shoulder since leaving last Sunday's game against the St. Louis Cardinals. The Cubs want to be careful with Rondon who had soreness in his right triceps recently but pitched in two games earlier this week.

Both moves were considered precautionary, according to a source.

Lefty Mike Montgomery will take Lackey's place in the rotation Saturday against the Colorado Rockies.

Zastryzny, 24, will become the first Cubs pitcher drafted (2nd round, 2013) by the current front office to make it to the big leagues with the organization. Pena, 26, has been in the organization since 2009. Both will pitch out of the bullpen for the time being.