Mulumbu lasted just 12 minutes after coming on as a second-half substitute in a disappointing 4-1 loss, receiving his marching orders after catching Joey Barton with his elbow.
The 28-year-old has protested his innocence, though, insisting that the decision of referee Lee Probert was harsh.
"I just jumped higher than Joey Barton," he said. "I didn't even know what player it was.
"I just jumped higher than him and I didn't make any movement with my shoulder. I think it's harsh but that's how it is.
"I didn't make any movement to hurt anybody so we will speak with the coach and the club and see what is the best way to sort this out."
Barton, who scored QPR's fourth at The Hawthorns, also came out in defence of Mulumbu after the game, stating the offence did not warrant a straight red.
