"I think we've been a better defensive team since the last time we played St. Louis, but we also probably haven't seen the firepower that St. Louis has, if they are at full strength," Blashill said. "I don't know how many players will be missing. The firepower that St. Louis and Colorado can throw at you is going to test us again defensively.
"How good are we in the D-zone? How good are we in the track? How good are we at protecting middle ice? As I have talked about lots, you have to be good in those areas to win on the road, otherwise you are just giving momentum away."
Detroit and St. Louis both enter Thursday's game with 13 victories this season. St. Louis is 13-8-4 overall and coming off a strong win against the 17-win Florida Panthers (4-3 Tuesday night). Detroit's record is 13-10-3, fresh off a 3-1-0 homestand.
The last time Detroit and St. Louis met, goaltender Alex Nedeljkovic made 34 saves to help Detroit snap a four-game losing streak and claim a 4-2 victory at Little Caesars Arena on Thanksgiving Eve.
Like the Red Wings, the Blues have been excellent on their home ice with an overall record of 8-3-1, and they're on a five-game home winning streak. On the road, Detroit is 4-7-1 this season.
On Wednesday, Blashill made it clear why Detroit has struggled on the road.
"I think there are two reasons why our home record is better than our road record and one of which we can't control, and that's our home crowd has been excellent as I've talked about lots," Blashill said. "Two, I don't think we've played winning hockey enough on the road. I think we've given the opponent momentum through poor puck decisions, through poor puck play and through, at times, not good enough defensively."