The Spanish giants announced Monday that the 26-year-old Argentina international will be sidelined for 6-8 weeks due to a muscle tear in his left hamstring muscle, his third leg injury this season.
Messi limped off after just 20 minutes of Barcelona's 4-1 win over Real Betis on Sunday and was replaced by Andres Iniesta.
"As many of you know, over the next few weeks I will be working full-time on the recovery of this new injury, for me it is a pity not to play with my team right now," Messi wrote on his Facebook page.
"Now what is most important is to recover well to help my team-mates and give back all the support you have given to me in the best way I know how to do, playing football. Thank you for your messages!"
The injury means Barcelona will be without Messi for up to eight matches, including its last two UEFA Champions League group games against Ajax and Celtic.
It was the third time this season that he has been forced off with a muscular problem following hamstring and thigh injuries in his right leg.
Messi suffered a bruised thigh during the first leg of the Spanish Super Cup against Atletico Madrid which kept him out for a week.
He then suffered a small muscle tear in his right thigh during a La Liga match against Almeria on 28 September which sidelined him for three weeks.
Last week Messi said on Chinese social networking site Weibo he was still not fully fit.
"Physically I am still not at 100 per cent but I am confident that as I play more matches I will recover my rhythm," he said.