Zetterberg didn't play Sunday night and Ken Holland says the team's leading forward is day-to-day.
He was hurt during Friday night's game against Montreal.
The Red Wings did welcome back forward Johan Franzen against the Panthers after he missed 16 games with a concussion.
Pavel Datsyuk was out for a 10th straight game with a lower-body injury and Holland says the centre is day-to-day. Jimmy Howard missed a third game in a row with an injured left knee and Holland says the goaltender might play Tuesday night at Philadelphia.
Forward Joakim Andersson missed his sixth straight game with a lower-body injury. He is expected to return against the Flyers or Friday night against Washington.
There was a lot of talk off the ice. From a player's standpoint, that's not the talk in the room. GMs make decisions, coaches make decisions, but as a team you have to come together and be ready to go, and we are.
— San Jose Sharks forward Tommy Wingels on his team's approach entering training camp