"We're going to try to play him with a ‘club,'" said McCarthy.
Barnett injured his hand near the end of the Packers' 35-0 loss to the Patriots, but McCarthy was uncertain exactly when or how the injury occurred.
Barnett is second on the team in tackles. He finished with three in Green Bay's 35-0 loss to the Patriots.
If Barnett is unable to play against the Seahawks, or is limited, rookie Abdul Hodge will take his place. Hodge has played mainly on special teams this season.
Other players who were injured, or aggravated prior injuries, include defensive tackle Cullen Jenkins (ankle), tight end David Martin (quadriceps and rib), linebacker Ben Taylor (hamstring), and cornerback Charles Woodson (shoulder).
McCarthy said that Woodson, Taylor, Martin and Jenkins were undergoing further evaluation of their injuries by team doctors today. Their status for next Monday's game will be determined Wednesday when the Packers return to practice to prepare for the Seahawks.