Yorke has hurt his hamstring against the Bulgarian side and limped off after ten minutes, making him a major doubt for their Premiership clash with Leeds United on Sunday.
With Matt Jansen and Andy Cole already sidelined, manager Graeme Souness would be left with Corrado Grabbi as his only available striker, although the Italian is himself still less than 100 percent fit.
"We have lost our two top men up front and we had problems in other areas with injuries," bemoaned Rovers boss Graeme Souness.
"Craig Short and Henning Berg both have back problems, Andy [Cole] has his hamstring and then the worst thing happened which could possibly have happened when Dwight had to come off with another hamstring.
"It's a major problem for us. He doesn't think he has damaged it but he did feel it and that's a concern."
One bonus for Souness was the debut of young midfielder Neil Danns.
"He has a fantastic attitude and that will mean he has a future in the game," he said.
"He's an aggressive boy and that's a big part of his game.
"You didn't see the best of him because it was more of a passing game and in an English game you see more challenges.'"
