The Cubs placed Milner on the 15-day injured list Saturday due to appendicitis, Taylor McGregor of Marquee Sports Network reports.
Milner will make his way to the 15-day IL after last appearing against the Mets on Thursday, when he failed to record an out while giving up an earned run on three hits. On the campaign, the 35-year-old has posted a 3.53 ERA, 1.21 WHIP and 18:9 K:BB in 35.2 innings. Tyler Ferguson will make his way up to the big-league club to fill the open spot on the roster.