Santi Cazorla says Arsenal must tie Hector Bellerin to a new contract as "it would be a mistake to let him go."
Bellerin, 21, who joined Arsenal from Barcelona as a 16-year-old in 2011, has three years left to run on his current Gunners deal.
However, Arsenal are keen to offer the Spain international an extension, sources have told ESPN FC, amid reports of interest from Manchester City and former club Barca.
"We'll see [what happens with Hector]," Cazorla told IBTimes UK. "It is clear that Hector is the right-back of the future. You could see in the [3-2] victory over Swansea [on Saturday] how good he is. He was all over the place and never stopped running.
"For Arsenal it would be a mistake to let him go. It is obvious that many teams want him. There has been talk about Manchester City and Barcelona. He is a player with great potential and I am sure he will also be a key part of the future of the Spanish national team."
Cazorla's Arsenal future has also been called into question of late, with the midfielder's current contract due to expire next summer.
The Spain international said previously that he is keen to sign an extension with the club and he has reiterated that he is happy at the Emirates Stadium.
"In my case I will finish my contract at the end of the season but I'm not thinking about it now," Cazorla said. "I'm just focusing on playing and giving my best on the pitch.
"Last season was very difficult for me after spending so much time on the sidelines [due to a knee injury]. Now I just want to enjoy myself again, and we'll see what happens in the future.
"I'm happy because I'm playing regularly. If I didn't play I would tell you that I would consider leaving, but I'm having minutes and I have the confidence of the manager. That's what every player wants.
"Since the very first day at this club I have had the affection of the fans, and that is amazing. I have only words of gratitude to the fans of Arsenal for how they've treated me from day one, and I try to repay them by giving my best on the pitch."