Morrow (back) was placed on the 10-day disabled list Wednesday, Mark Gonzales of the Chicago Tribune reports.
Morrow first felt tightness in his lower back Monday, and the issue is apparently bothersome enough to warrant a stay on the shelf. The move is retroactive to Sunday, so Morrow will be eligible to return in one week if he ultimately proves ready. Justin Hancock, who served as the 26th man for Tuesday's doubleheader, will stick with the Cubs to take Morrow's place in the bullpen. Justin Wilson saw the first save chance in Morrow's absence Tuesday, but he blew the opportunity and took the loss, so it's unclear if he'll see additional save opportunities with Morrow on the shelf. Pedro Strop and Steve Cishek could also factor into the late-inning mix until Morrow is healthy.