It now seems likely that Cotterill will be allowed to leave if United offer around £2 million for his services. Cotterill cost the Latics £2.5 million from Bristol City two summers ago.
Blackwell said: "I hope to tie up a deal for a wideman soon. Cotterill is desperate to come back and Martin has made it clear that he feels the same.
"There's a possibility that we could get both, there's a need to change games and strength in-depth is massive for this division. We've got options."