Paul Trollope is hoping that he will know more about the extent of Luke Daniels injury within the next 24 hours.
The manager is doubtful that the keeper will be available for the start of the season, and says that he does have other options if the news is bad.
He told bristolrovers.co.uk: "Our medical staff are speaking to West Brom's medical staff and we are still looking at the rehab times and the potential of him coming back or having to stay at West Brom for a longer length of time.
"We are not sure yet, we are going to get some advice from both doctors as to the way forward.
"Obviously we would like him back as soon as possible, we have signed him on a year loan and identified him as the one who could be our number one throughout the season.
"These things happen sometimes and we will probably know more at the end of the day.
"He is not going to be out for six months or a year, but at the moment we are unsure whether it is going to be a couple of weeks or a couple of months, but with our situation and with the season starting next week, we need some quick answers.
"We identified all possibilities and we did not put all our eggs in one basket, and we have other possibilities if the news is bad and we have to look elsewhere, but we will have to move quickly.
"It does look like Luke will be missing the start of the season for sure. Mike Green has done well, especially in the last two games."
Mike Green has impressed during his two games between the sticks, but the manager insists that we needs two keepers in the building.
He said: "Mike has made very few mistakes, made some good saves, kicked it well and looked to have made the progress we hoped he had.
"The keeper at the under 18s is not near the level at the moment to come into contention, so if Luke is not available for the opening games we will need to bring someone in."
Rovers do not play a friendly this weekend, so they have a bit more time to prepare for the visit of Premiership side Stoke on Tuesday.
Trolls said: "It gives us a little bit more training time. We will have to look at a few people on Tuesday,
"Stoke will be a big test, it will be a competitive game and the aim is to get us right up to speed for the season.
"We will go in strong, but we will probably see a few changes at half time and early in the second half, try and look after people for Saturday, but we will go as strong as we can with the starting 11.
"It will be a fantastic game for us against an established Premiership team, who are strong and I don't think get the credit for some of the football they play.
"We will be pleased to have Tony back at Rovers after his fantastic service, and we are pleased that they are coming down."
And the manager is continuing his search for a target man, and is confident about bringing someone in before the window closes.
He said: "We are on the case and we have got a number of possibilities. We do need that other option, we are not hiding from that fact, and the sooner the better really.
"If it is before Peterborough that will be great, if not we have until the end of the window to do business, and I am pretty sure that before then we can do something."
Stuart Campbell missed last night's game at Cheltenham with a sore hamstring, but will be back in training tomorrow.
Trolls said: "It is nothing to worry about, just a tight hamstring, we believe his back and his pelvis were a little bit out of line which caused a little bit of discomfort in a hamstring.
"Stuart is fine and will join in with the group for a double session on Friday."
