Portis has been ruled out for Wednesday's game against Detroit due to a right elbow contusion, Eric Nehm of The Athletic reports.
Portis hadn't appeared on Milwaukee's initial injury report before he was unexpectedly ruled out approximately 90 minutes before tipoff. Starting center Brook Lopez has logged at least 35 minutes in three of Milwaukee's last six games, and a similar workload may be in store with Portis unavailable. The Bucks could also need Taurean Prince to pick up extra minutes at power forward, while rookie Tyler Smith could be a candidate to enter the rotation.