The start of Hargreaves' second season at United was hampered by injuries, specifically a recurring patellar tendinitis problem that restricted him to sporadic appearances in 2008–09. After trips to specialists in both London and Sweden yielded no results, Hargreaves travelled to Colorado, United States, in November 2008 to visit renowned knee surgeon, Richard Steadman.[5][6] Hargreaves underwent surgery on his right knee on 10 November 2008 and received a similar operation on his left knee in January 2009. However, this meant that Hargreaves would miss the remainder of the 2008–09 season, ultimately meaning he would miss out on a second Premier League title and a League Cup winner's medal.[7] Hargreaves underwent his rehabilitation programme in the United States, and was due to return to training with Manchester United at the Audi Cup in Munich. However, upon assessment, it was decided that he should continue with his rehabilitation in the United States.[8] Hargreaves returned to Manchester United on 23 September 2009, joined by his physiotherapist for a week to aid the transition process and for the club to understand his rehabilitation programme. [9]
In January 2010, it was speculated that Hargreaves was initially slated to return in time for Manchester United's Champions League first knockout round tie against Milan, despite not being fully match-fit.[10] However, on 4 February 2010, Hargreaves suffered a major setback to his World Cup hopes as Sir Alex Ferguson omitted him from the squad for the knockout stage in favour of Belgian defender Ritchie De Laet.[11] It was expected that Hargreaves would make his return from injury in a reserve team match against Manchester City on 11 March,[12] but on the day of the match, Hargreaves pulled out of the game to continue with his training regime.[13] He eventually made his comeback a week later, playing for 45 minutes of Manchester United's reserve team match against Burnley on 18 March.[14]