The England forward is hoping the Gunners can keep hold of the reported Manchester United target, whilst admitting he expects new faces to arrive at the club over the summer
Nasri, who only has one year remaining on his contract, has recently refused to rule out a move to the Gunners' fierce rivals Manchester United and Walcott has conceded anything could happen over the summer.
“I don't like getting involved in people's careers,” Walcott told Sky Sports News.
“We need to keep hold of our best players - but it's up to Samir, it's his decision.
“He had a great season, he showed people what he can do.
“He's a very important player to Arsenal and we'll see what happens in the summer."
Walcott also admitted that he is expecting fresh faces to arrive at the club over the course of the summer, with reports linking a host of names from Europe to the club.
"Yeah [I'm expecting players to be signed], the manager's said so," Walcott added.
"Hopefully we can keep hold of our best players, as we need to be winning something next season without a doubt.
“It's been so long and the fans have waited so long. And players don't like seeing every season go without winning anything."