It's the same knee that caused Howard, one of the Team USA Olympic goalies, to miss much of December.
"He got hurt. The same knee, I guess," Red Wings' coach Mike Babcock said.
Howard is day-to-day.
Detroit came into the game missing several regulars because of injuries.
Mrazek made 13 saves.
"Well I think we obviously were not good enough from our side," Detroit captain Henrik Zetterberg said.
"Still we had it 1-1 after the first, had some good looks on the 5-on-3 (in the second period) there and couldn't really get it going, but in the third their fourth goal kind of ended the game tonight."
Jackman broke a 1-1 tie with a screened one-time shot from the high slot at 1:01 of the middle period with the teams playing 4-on-4. It was Jackman's third goal of the season.
Shattenkirk's goal was on the power play and came on a screened shot from the left point 2:21 into the period. It was Shattenkirk's seventh goal.
"There was no chance. ... There was no way Howie was going to see any of those," Hitchcock said. "We had two big bodies at the net all the time."
Jackman added: "We had a lot of guys going into the hard areas of the ice. It's a lot easier to get the puck through."
Nyquist's power-play goal tied the game with 27 seconds remaining in the first. He controlled and put in a loose puck during a goalmouth scramble for Nyquist's sixth goal and his first in nine games.
"They got the power-play goal late in the first period, but we got the momentum back." Bouwmeester said.
He got his fourth goal, 2:14 into the third, when his shot from the left point went in off the Red Wings' Riley Sheahan.
The game was tied at 1 after the first 20 minutes despite St. Louis outshooting Detroit 18-7.
Paarjarvi opened the scoring with 8:47 left in the opening period when he banked one in off Howard's leg on a wraparound from behind the net. It was Paarjarvi's fourth goal.