Alexander has been given a five figure sum to strenghen the Imps' squad and Rob Bradley is confident Alexander will spend it wisely.
He said: "Keith manages his budget very well and I am pleased to confirm that he now has more money at his disposal.
"This means he will be able to bring in one or two more players, such as a quality striker, if he chooses to.
"We are very grateful to the benefactor, who wishes to remain anonymous" he added."