Messi, who struggled with the problem in the early part of the season, further aggravated the injury in Barcelona's 4-1 win over Real Betis at the weekend.
Subsequent tests have revealed that Messi could be out of action for the next two months, with a January return expected.
"Everybody knows the importance of Leo to this team," the 33-year-old told Mundo Deportivo.
"Leo makes the difference and there is no player in the world capable of doing what he does. But he will be okay: he will be back and it will be great to have him playing again."
Barcelona currently top La Liga with 37 points.