Eto'o spent just one season with the Blues, scoring 12 goals in 35 games, including a hat-trick against Manchester United in the Premier League.
|15/8||Chelsea are 15/8 with Bet365 to win the Premier League in 2014-15|
"Contrary to what a puppet says about my age, I am still physically fit," he said. "At 33, I feel really good. I have proven that I can do better than the younger players."
It was revealed in May that Eto'o has been in talks with Guangzhou Evergrande over a move to China this summer.
Chelsea also confirmed Ashley Cole's exit from Stamford Bridge after eight seasons and 338 appearances in a spell which saw the club win the Champions League, Premier League and the FA Cup four times among other trophies.
"Chelsea Football Club thanks Ashley for the fantastic service he gave throughout his eight years here, and for helping to bring so many trophies home. We wish him well for the future," a club statement read.
Portuguese goalkeeper Hilario, who spent much of his time at Chelsea as deputy to Petr Cech, has also left the club.