Source: Toronto FC turned down $5 million bid for Michael Bradley

The Toronto FC star and U.S. national team captain was the subject of a $5 million transfer offer that the MLS club rejected, a source confirmed to Goal USA.

Michael Bradley has been sidelined with a knee injury since the Copa America Centenario, but that time away hasn't cooled off interest in his services from clubs in Europe.

Toronto FC recently rejected a $5 million transfer offer for Bradley from a team in one of Europe's top four leagues, a source with knowledge of the offer confirmed to Goal USA.

Though it remains unclear which team stepped up with the bid, recent reports in Italy have linked Serie A clubs Sampdoria and Torino with interest in the former AS Roma midfielder.

“We regularly get interest for Sebastian [Giovinco], Jozy [Altidore] and Michael -- all of them,” TFC general manager Tim Bezbatchenko told the Toronto Sun last week .“It’s a matter of understanding that these players aren’t for sale. Again, if there was an offer we couldn’t refuse, then it’s something we would entertain but for the most part it’s a polite decline -- thank you but no thank you.”

Bradley spent parts of three seasons playing in Serie A, first with Chievo Verona in 2011-2012, then with AS Roma from 2012 until January of 2014, when he completed a $10 million move to Toronto FC.

To put the $5 million offer in perspective, a transfer of that size would be among the largest ever paid for an MLS player. Only Jozy Altidore's $10 million move to Villarreal and Eddie Johnson's $6 million transfer to Fulham (both in 2008) have been larger.

Bradley already holds the record for largest transfer fee ever paid by an MLS team, with his $10 million move from AS Roma to Toronto FC surpassing Clint Dempsey's $9 million move from Tottenham to the Seattle Sounders.

Bradley, who turned 29 on Sunday, returned to training with Toronto FC on Tuesday after having recovered from a knee injury suffered in the U.S. loss to Colombia in the Copa America third-place match.