Former Manchester City defender Micah Richards believes injuries prevented him realising his full potential with the club.
Richards was a key member of the side that won the Premier League title in 2012, but was then hit by a succession of problems while Pablo Zabaleta became first-choice right-back.
The 27-year-old spent last season on loan at Fiorentina before joining Aston Villa on a free transfer this summer, ending a 13-year association with City.
Richards told City TV: "I didn't ever expect to do what I have done, but with my injuries I think I was hampered a lot. I think I could have achieved a lot more.
"I think my best years are ahead of me. It is sad to be leaving at this time."
The former England international hopes that the move to Villa Park will reinvigorate his career.
He said: "I do believe that, when I am 100 percent fit and firing, I am a very good player. My problem over the last couple of years has been picking up injuries and getting that consistency of playing."
