Banahan was dismissed in the 66th minute at Franklin's Gardens
Bath wing Matt Banahan has been banned for two weeks after being red-carded against Northampton on Saturday.
Banahan was dismissed for stamping on Saints fly-half Stephen Myler during the hosts' 15-13 win.
Banahan, who started all three of England's autumn internationals, was sent off in the 66th minute by referee David Rose.
The suspension means Banahan misses Bath's back-to-back Heineken Cup fixtures against Edinburgh.
Bath head coach Steve Meehan said before the ruling: "It didn't look like a red card.
"Myler said that he [Banahan] made contact with his forearm, but the assistant referee said he made contact with his head.
"The referee wasn't influenced by anyone except the assistant referee, who told him it was a red card."
Meehan's side currently sit bottom of their Heineken Cup pool having lost both their opening matches, while they lie second-bottom of the Guinness Premiership with 12 points from their opening 10 fixtures.