Michael Ballack has admitted he regrets leaving Chelsea in 2010 as he planned on retiring at the Premier League club.
The former German midfielder had aspirations of ending his career in west London but Chelsea only offered him a one-year deal at the end of the 2009-10 season.
Ballack wanted a two-year contract but Chelsea's policy only allowed players over the age of 30 to sign one-year extensions.
Their reluctance to give in to Ballack's demands saw the Germany legend return to Bayer Leverkusen for the final two years of his career but he has revealed he made a mistake.