Lambert had to play Adam Drury at right-back in the 3-1 win at Stockport on Saturday as Jon Otsemobor, Michael Spillane and George Francomb were ruled out and he knows he desperately needs to bring in cover.
"Adam did great. But this club only has one recognised right-back, which is strange, strange," said Lambert. "We have to try to address it. I hope Jon will be back next week and then we'll try to get somebody in because one right-back is never enough."