Six days after tantalizing rumors first linked Michael Bradley to a return to Major League Soccer, Toronto FC made it official on Monday.

The longtime US national team mainstay strolled onto the stage during a press conference in Toronto as the newest member of a revamped TFC squad, ending nearly a week of speculation if he would suit up in MLS for the first time since leaving for a career in Europe in 2005.

"I can tell you I have never been more excited or more motivated for any challenge in my entire career," said Bradley, who joins the team as a Designated Player.

Bradley’s former club – Serie A side AS Roma – announced Thursday they had sold Bradley’s rights for $10 million, the the biggest incoming transfer fee in league history.

“To acquire a star midfielder like Michael Bradley, seen by many as the top American player in the world, alongside a premier striker in Jermain Defoe, makes this a groundbreaking day for Toronto FC and for Major League Soccer,” Maple Leaf Sports & Entertainment president and CEO Tim Leiweke said in a statement. “We have worked hard this offseason to deliver a winning team to our fans and I would like to thank AS Roma and MLSE ownership for their commitment and support. This is an exciting day for Toronto FC fans and we can’t wait to start the season.”

Bradley, 26, has been capped 82 times for the USMNT over the past eight years, and is generally regarded as one of the most crucial players in Jurgen Klinsmann's squad. He starred under Bob Bradley, the previous USMNT head coach and Michael's father, in both the 2010 World Cup as well as the 2009 Confederations Cup and 2011 Gold Cup.

“This certainly goes down as a tremendous day in Toronto FC history and goes a long way towards delivering on our promise to our fans of building them a winning club,” Toronto FC general manager Tim Bezbatchenko said in a statement.

“We had a number of goals heading into this season that included building this club with both a short- and long-term vision for contending for playoffs and championships, while also being recognized and competitive internationally. Adding star players like Jermain and Michael, and partnerships with world-class clubs like Tottenham Hotspur and AS Roma, will help us a great deal in reaching those goals.”

The central midfielder began his career in MLS with the MetroStars in 2004, at the age of 16, missing his first season due to injury before winning a starting role in 2005. His tactical understanding on both sides of the ball impressed, and an offer from Heerenveen that winter saw Bradley make the move to the Netherlands.

While his European career has been a long and steady rise ever since and he is a gameday regular for Roma, Bradley hasn't been able to nail down an everyday starting job under first-year manager Rudi Garcia, whose midfield includes Italian legend Daniele De Rossi, Dutch international Kevin Strootman, and newly acquired Belgian hard man Radja Nainggolan.

“It’s a shame Bradley is leaving, but he wanted to go and we cannot keep hold of a player who doesn’t want to be here," the Roma manager said last Thursday. "It's a pity and I understand he wanted more playing time.”

Bradley’s reported $10 million transfer fee is the third-highest for an American player all-time, behind two deals for striker Jozy Altidore. Major League Soccer sold the young striker to Spanish side Villarreal for $10 million in 2008, and Dutch side AZ Alkmaar sold him to EPL side Sunderland for $13 million last summer.

The Bradley signing is the third major pickup in less than a week for Toronto FC, who officially introduced English international striker Jermain Defoe on Monday and brought back Canadian international Dwayne De Rosario last week.