Arsene Wenger says failing to secure Alex Oxlade-Chamberlain's future at Arsenal would do "big damage" to the club.
The 23-year-old's current deal expires in 2018 and there has been speculation that he could be sold this summer.
Oxlade-Chamberlain, signed from Southampton in 2011, recently returned from a hamstring injury but has not started a match for almost a month.
However, Gunners boss Wenger insists he wants Chamberlain to extend his contract at the Emirates.
"I personally think it is vital that Chamberlain stays at Arsenal," he said.
"We bought him when he was very young, we have built him up and I think he has a great mentality.
"I like his mentality and he has a good football brain. It would be a big damage for us to lose this kind of player."
The England international is one of a number of Arsenal players whose contracts expire next year and who has yet to agree an extension.
Jack Wilshere, Mesut Ozil, Alexis Sanchez and Kieran Gibbs also have 14 months remaining on their current deals.
Wenger, whose own contract expires at the end of the season, is adamant that the club will not change its wage policy - even if it means losing key players.
"In an inflationary market we have to consider the situation as a whole," Wenger said. "We have to dedicate the money for everybody.
"We always had that attitude. We have sold players in the past who we didn't find agreements with just because we wanted to respect and needed to respect our balance."
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