Former Arsenal goalkeeper Jens Lehmann has called on Alexis Sanchez to "stop sulking" after the Gunners lost four of their last five matches in the Premier League.
Sanchez is one of a number of Arsenal players to come under fire for their recent performances after they dropped to sixth place in the league table and were embarrassed by Bayern Munich in the Champions League.
Lehmann - who won the Premier League with Arsenal in 2004 - has also questioned Mesut Ozil's displays, as well as the £35m fee which the club paid Valencia for defender Shkodran Mustafi.
The 47-year-old told The Sun: "They talk about Sanchez being a big player but if you are sulking, you can't be a big player. You must be a big player mentally, not just be good at dribbling.
"There's always a question with Ozil - how much can he contribute when it gets tough?
"It's not Mustafi's fault someone has paid £35m for him. If someone buys me for £35m, the next day I'm not a better player. He is giving everything. But sometimes the team concede five, so he has to ask himself if it's good enough?"
Manager Arsene Wenger has claimed that contract talks with Sanchez and Ozil will not commence until the summer.
