The CFL club placed him on the nine-game injured list Tuesday after he was hurt in the Bombers' 45-23 home loss Sunday to the Saskatchewan Roughriders. The loss of Lobendahn is a big one for Winnipeg, which faces the Montreal Alouettes on Sunday with top spot in the East Division on the line.
The Bombers also listed quarterback Buck Pierce as day to day with bruised ribs.
He was picked off five times and was hit hard on several occasions in the loss.
Pierce suffered a rib injury on Winnipeg's opening possession. On the Bombers' next series, he was hit so hard that his helmet went flying.
Both times, he stayed in the contest. Pierce was limited to just five starts last year due to knee and elbow injuries.