The Cubs put right-hander Alec Mills on the injured list Sunday, as expected, after being forced from Saturday’s start in the first inning by back pain.
Mills said after Saturday’s game that the pain was similar to what he experienced in spring training, when the lower back strain forced him to open the season on the IL.
Between that back injury and a subsequent quad injury suffered during his rehab, Mills didn’t make his season debut until June 7.
The Cubs have no timeline for his return.
Right-hander Michael Rucker was recalled from Triple-A Iowa Sunday for his third stint with the Cubs, rejoining a bullpen that was to be without at least Mark Leiter Jr. (5 1/3 innings Saturday) and Mychal Givens (two innings) after they picked up heavy workloads in Saturday’s 3-1 victory over the Red Sox.
Rucker has appeared in 12 games for the Cubs this year, allowing 12 runs in 19 2/3 innings.