He has also today recalled striker Rakish Bingham from his loan spell at Hartlepool for the final push.
New signing Blair was stretchered off in Saturday’s dismal 2-1 defeat at relegation rivals Carlisle United with what looked a serious knee injury and could become the third major signing this season to face a long term lay-off.
Blair is seeing a specialist today for a scan and the club hope to know more about the injury later today or early tomorrow.
With the January window closing tonight, Murray said: “There may be a couple of things depending if they can be done. We do have irons in the fire.
“In areas that are very important to us, I think we are still lacking a bit of substance. We are going to need men for this battle.
“Down the spine of your team you need your rocks. When you are in a winning position or when you are drawing games and need to see it out, these are the people that carry you through.
“At the minute we have a lot of intelligent players, a lot of flair players. But for me we are missing that little bit of grit.
“I think we do have good players here. But at the minute they are suffering with a lack of confidence in themselves because they have put in a hell of a lot of work and are not getting the results. As a player that will affect you.”
Mansfield this morning recalled striker Bingham from his loan spell at Sky Bet League Two rivals Hartlepool United.
During his one month stay at Victoria Park, the 21-year-old made five appearances for Hartlepool and scored one goal in a 2-0 victory over Cheltenham Town.