Favre was hurt in the second quarter of Monday night's 40-14 loss to the Bears when Chicago defensive end Corey Wootton wrapped him up and slammed him to the cold artificial surface of TCF Bank Stadium, knocking him out of the game.
The 41-year-old quarterback landed on his left shoulder, taking another beating after overcoming a sprained right (throwing) shoulder to make a surprise start in the contest.
Frazier told reporters Favre won't go on injured reserve and may yet make an appearance in the Vikes' final two games.
"The fact that Brett was able to play was a miracle in a lot of ways," Frazier said. "He's proven time and again he's capable of coming back and playing."
The Minnesota coach indicated injured star running back Adrian Peterson might play Sunday night against the Philadelphia Eagles.