"It is the manager's decision but yes, I love Kei (to stay)," said Martin. "I think he has brought so much here. He has been a breath of fresh air, really.
"And I think he's not just a good lad, he's a really good player. He has been really effective and I think he did great for us again at Sunderland.
"I think he's been brilliant. He has surprised all of us, to be honest. You never know what you are going to get. The MLS is getting better and better, but you're never sure what you're getting.
"He has not had games and he had a bit of time off before he came over, so for me he will only keep getting better and it is up to him to decide his future, really. If he keeps it up, then I'm sure we will be more than interested in keeping him."