Alexis Sanchez has just 18 months left on his contract at Arsenal and is yet to agree terms over a new deal.
Arsene Wenger has repeatedly said that he is confident the Chile international will commit his future to the club.
Sanchez was seen storming off the pitch when the Arsenal boss subbed him in the 4-0 win over Swansea last weekend.
Alexis Sanchez has just 18 months left on his contract
Granit Xhaka believes Alexis Sanchez is the model professional in training
But Xhaka insists Sanchez sets the standard for the Arsenal players on the training pitch.
"Alexis Sanchez can be a really big role model," he said.
"The reason is that he always goes to his absolute limit in both training and in the game.
Alexis Sanchez furious after being substituted against Swansea
Sat, January 14, 2017
Alexis Sanchez was not happy to be subbed off during Arsenal's win over Swansea
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Alexis Sanchez scored during Arsenal's win over Swansea
"I think that attitude and application is something that any players can take something from."
Like Sanchez, Mesut Ozil is also yet to put pen to paper on a new deal and Xhaka believes it is imperative Arsenal tie up the star duo to new contracts.
"It is so important for us because this is a really big phase of our season," Xhaka added.
"We need everyone fit and to stay healthy in the upcoming months as well. Of course, the contracts are a positive both for the players and the club as well."