Villanueva (knee) was a limited participant this week in practice and is considered questionable for Monday night versus the Colts.
The 33-year-old suffered a knee injury in the Ravens' Week 4 matchup against the Broncos. He was able to participate in some capacity in this week's practices but will nonetheless carry a questionable tag into the contest. Patrick Mekari will be in line for a start if Villanueva can't play.