Larsson's current deal runs out in the summer and Newcastle are reported to be interested in the Sweden international.
But Grant told Press Association Sport: "The manager (Alex McLeish) has spoken to Seb's agent (about a new contract) and it's ongoing. I think Seb would obviously be keen to stay - and the club are looking for him to stay also."
He added: "But it's down to him and his agent who is speaking to the club at the moment. That's as far as it's gone.
"We're not kidding ourselves on. We just hope that Seb wants to stay with us.
"I'm sure that's the case and I think he's proved that with his performances this season.
"But, if he decides to move elsewhere, you can't do anything about it. That's the situation with the Bosman ruling now.
"Sometimes the big players have the opportunity and the agents can make that happen."