Manchester United's Bastian Schweinsteiger warms up before the match between Manchester United and Saint-Etienne on Feb 16, 2017. [Photo/Agencies]

CHICAGO - Former Germany captain Bastian Schweinsteiger is leaving Manchester United after signing with the Chicago Fire of Major League Soccer, the English club confirmed on Tuesday.

Schweinsteiger, a key member of Germany's 2014 World Cup-winning team, heads to North America after a difficult stint at United, where he was frozen out by manager Jose Mourinho.

The 32-year-old, who scored 24 goals in 121 appearances for Germany, will join Chicago subject to passing a medical and obtaining a visa.

"I am sad to leave so many friends at Manchester United," Schweinsteiger told United's website.

"But I am grateful to the club for allowing me the chance to take up the challenge as a member of the Chicago Fire."

Schweinsteiger, who is married to now retired former women's tennis world No 1 Ana Ivanovic, expressed his thanks to his teammates - and Mourinho.

"I've enjoyed working with the manager, the players and staff here and wish them all the best in the future," he said.

"But I have to reserve special thanks to the United fans, whose support has been a very special part of my time in Manchester.

"I was delighted to be part of the squad that won the FA Cup for them last season and will always remember their energy and their passion.

"Now is the right time for me to start a new chapter in Chicago and I am looking forward to it."

United limited its tribute to one line, with no comment from Mourinho.

"Everybody at United would like to wish Bastian the very best of luck in his new career in the United States," the club said on its website.

On Monday, Chicago Fire general manager Nelson Rodriguez said the signing of Schweinsteiger brought added responsibilities and expectations for the team's performance.

"We're adding someone who has won at every level, including the very highest levels, and has done so in a way that is consistent with our values," Rodriguez was quoted as saying by the Chicago Tribune.

"We will now be forced to hold ourselves to a higher standard, an accountability level.

"Previously, I think we could satisfy ourselves with what is known domestically. Now we need to rise to a standard that is set more internationally."

Schweinsteiger played his entire club career with German giant Bayern Munich before being signed by Manchester United in 2015 when Louis van Gaal was in charge at Old Trafford.

The Tribune cited an unidentified club source as saying Schweinsteiger had signed a one-year deal worth $4.5 million, a salary that makes him one of the highest-paid players in MLS.

"Throughout my career, I've always sought opportunities where I hoped to make a positive impact and to help make something great," Schweinsteiger said.

"My move to Chicago is no different.

"Through my conversations with Nelson and (head coach) Veljko Paunovic, I'm convinced by the club's vision and philosophy and I want to help them with this project."

Paunovic said the seeds of Schweinsteiger's move had been sown by a lunch with the German star in Manchester last year.

"The conversation was so spontaneous, so natural and so inspiring for both sides," Paunovic said.

"At one point it became a very personal conversation. I think that also helped for both sides to understand how we can help each other and how much value we can get from this for both sides."

The Chicago team has endured a mixed start to the new MLS season, taking four points from its opening two games before being pounded 4-0 by the expansion FC Atlanta last weekend.

Chicago has lifted the MLS Cup once, in 1998. For the past four seasons the team has failed to reach the playoffs.

Agence France-Presse