3. Owen Hargreaves
Dave Thompson/PA Archive/Press Association ImagesOwen Hargreaves is the third former Manchester United star on this list to make the unusual switch to Manchester City but he never stuck around long enough to do his former side any damage. Hargreaves had spent four injury-plagued seasons at Old Trafford, and his career was wrecked by a recurring patellar tendinitis problem that limited him to just 27 appearances at United. That didn't deter City from making a move in 2011, however, after the Red Devils released the stricken midfielder. The Citizens were looking for a replacement for Patrick Vieira, who had just announced his retirement, and were mindful that Yaya Toure would be absent for the month of January due to the Africa Cup of Nations. They looked at Daniele De Rossi,Fernando Gago and Mark van Bommel, but somewhat surprisingly opted for Hargreaves, Predictably, it was a poor decision. Hargreaves did score for City, on his debut no less in a League Cup game against Birmingham City, but that was one of only four appearances he managed for the Citizens, and with injury woes flaring up again, arguably one of football's most tragic players announced his retirement one year later.