Daniels, signed from the Baggies on a season-long loan, was forced to miss the match, which Rovers lost 1-0.
Rovers manager Paul Trollope told BBC Radio Bristol: "He's gone back to West Brom to be assessed thoroughly."
Daniels was first affected by a back injury towards the end of last season but showed no signs of discomfort during Rovers' trip to Scotland.
Trollope continued: "It's disappointing because Luke has made a big impact on the squad. I think everyone was looking forward to seeing him on Saturday.
"But these things happen and now we have to make sure that he is assessed quickly. Hopefully we will know more in the next 24 or 48 hours."
Mike Green deputised for Daniels against West Brom, and could stay in goal when Rovers continue their countdown to the new campaign at Cheltenham on Wednesday.
Source: BBC Sport
Source: BBC Sport