The 24-year old left-back is reported to be keen on departing Ewood Park this summer following the clubs relegation to the Championship with Southampton showing interest.
"The way it worked with Martin was when he was away, there was a lot of interest in him," Kean told the Lancashire Telegraph.
"I have sat down with Martin and said to him we want him to play. He is getting over a groin operation, is probably not going to be fit for the start of the season, but I have said we want to keep him and want to look at extending his contract.
"I think there were clubs who enquired and we said 'not for sale'."