Datsyuk will miss his sixth consecutive game with a lower-body injury. Howard hasn't played since leaving in the third period of Saturday's 4-2 win against Toronto with a left shoulder injury.
Both players hope to be back in the lineup on Saturday when Detroit visits Nashville.
"It's getting better," Howard said Wednesday. "Still a little stiff and soreness in there."
Thomas McCollum will back up Joey MacDonald against the Blues.
Forward Kris Draper and defenseman Ruslan Salei will be healthy scratches against the Blues.