The club don't need to sell him so I can't see us accepting a low-ball offer for him, I'm sure they value him at around £1.5m+. That being said, I'd be greedy and keep him, it's a long season and we can't bank on Knockaert et al staying fit. Kaz is a very good understudy winger at this level.
A good idea to turn down £1.5M (not that we'd get hat much) and carry on paying him maybe £ half a million a year, for mainly not playing? Doesn't sound like good business to me.
It's not like we're Man. City or Chelsea who can just afford to keep buying players just to stop them playing for anybody else.