He told the Yorkshire Evening Post: "I'm still at (Manchester) United and it's a matter of going back on the first of July and speaking to the gaffer.
"I enjoyed my time at Sheffield United and would definitely go back if an offer came in. But it's out of my hands."
Martin was impressed by manager Kevin Blackwell and believes the Blades should challenge for promotion to the Premier League in the new season.
He said: "They definitely have a great chance. I think they have got one of the strongest squads in the Championship and with the gaffer, Kevin Blackwell, they've got a really talented manager.
"It's a massive club which belongs in the Premiership.
"They know they have to get there next season and after such a strong finish under Kevin they will fancy their chances."