Schalke's chairman on Sunday threatened to banish their Bayern Munich-bound midfielder Leon Goretzka to the stands for the rest of the season if he fails to perform for the Royal Blues.

Both clubs said on Friday that the 22-year-old Goretzka will join Bayern next season on a free transfer after five years with Schalke.

The Gelsenkirchen-based team say they did "everything possible" to keep Goretzka, who can expect a backlash from home fans if he plays against Hanover 96 at home on Sunday in the Bundesliga.

A win would move Schalke up to second in the table behind Bayern and club chairman Clemens Toennies has said he will insist Goretzka be banished to the stands if he under performs in the time left.

"I hope he will play a second-half to the season of his life," Toennies told Sky Sports News.

"However, if it is better for the team, then it could also be the case that Leon Goretzka sits until the end of the season in the stands."

Goretzka broke into the Germany squad when a young team minus their World Cup-winning stars lifted the Confederations Cup in Russia last July by beating Chile 1-0 in the final.

He is poised to retain his Germany place for the World Cup finals, but his chances of playing in Russia would be damaged if Toennies follows through with his threat.

"I am not declaring myself as his enemy, but we can't allow the goals of the club to be endangered," Toennies added.

The Schalke boss feels Goretzka is joining Bayern too soon as he follows the path trodden by Germany captain Manuel Neuer, who also quit Schalke for Bayern in 2011.

"Personally, I think it's too early. He should have stayed two more years and then gone as a big star," said Toennies.

"It was his decision, we have to accept that and Schalke 04 won't go under because of it."