Rovers signed Wayne Andrews from Coventry City but the big striker's debut lasted only 17 minutes.
He was stretchered off after a crunching tackle by Yeovil skipper Terry Skiverton and his manager Paul Trollope said: "We have to assess the damage but it looks like knee ligaments and it could be serious.''
Yeovil's new boy was Portsmouth goalkeeper Asmir Begovic. They had to hurry for a replacement when Scott Flinders was recalled by Crystal Palace and manager Russell Slade said: "Kevin Bond had him on loan at Bournemouth and he rated him highly. He certainly did a good job for me.''
Begovic went home with the man-of-the-match trophy after three outstanding saves.
In first-half stoppage time he did well to tip over a Rickie Lambert header from a Stuart Campbell corner.
But his two best saves came near the end. In the 78th minute Campbell set up Chris Lines and the keeper saved with his feet.
Then, three minutes from time, Begovic flew across his goal to tip over a Campbell free-kick.
Yeovil also introduced left-back Nathan Smith who, until a fortnight ago, was working on computers and playing as a part-timer for Potters Bar in the Ryman League.
Slade said: "He was recommended to me and I have been very impressed. I have now put him on contract for next season and he's down here full-time.
"I thought he was excellent today. His only mistake came two minutes from the end when he was caught in possession and providing he works hard he should have a bright future.''