Derby County defender Mitch Hanson has joined Port Vale on-loan to the end of the season.
"He is a player I am looking at for the future. He can play at centre-back or at full-back, but he won't be able to join us for 10 days because of his injury," Sinnott told the club's official website.
"If I had waited until he is over the injury, we wouldn't be able to look at him until the summer, so it makes sense to get a look at him now rather than later."