The wide receiver, whom the Seahawks acquired in a trade with the Minnesota Vikings during the off-season, is yet to play this season, having undergone surgery at the start of August.
The head coach told NBC Sports: "I don't think [Harvin playing against the Arizona Cardinals next week] is realistic. I think that is too soon to expect that to happen.
"We want him to be able to endure the rigors of the end of the season. It's not important to rush him back, it's important to wait it out and be patient and get him out there when he's ready to go and withstand the load of the game."
The Seahawks top the NFC West, having won four of their five games so far this season.