The right-hander, being switched from the bullpen to the rotation, was making his third start. He allowed two hits, struck out two and walked one.
Feliz will be re-evaluated Wednesday.
Ryan Dempster gave up two runs and four hits in six innings, the longest outing for the Cubs pitcher this year. He allowed Dustin Brown's two-run homer in the second.
Engel Beltre walked with the bases loaded in the eighth and Conor Jackson had an RBI single.