Messi sent a burofax to the club on Tuesday, asking for his contract to be terminated, so he can leave for free.
Puyol, who played with Messi during the early stages of the Argentine’s career, took to Twitter to post a message in Spanish which translated as: “Respect and admiration, Leo. You have my full support, my friend.”
Suarez, who is also rumoured to be leaving the Camp Nou this summer, replied by simply posting two applause emojis.
Messi is believed to have been considering his future, since Barca were thrashed 8-2 by Bayern Munich in the Champions League quarter-final.
Before then, the 33-year-old had fallen out with a number of senior figures behind the scenes at the club, including former director Eric Abidal.