Barcelona also left injured defenders Carles Puyol, Javier Mascherano and Jordi Alba out of its squad for the trip to Glasgow.
That means that Marc Bartra will probably start again in the centre of the defence alongside Gerard Pique. The little-used Bartra played perhaps his best game for Barcelona in Saturday's 2-0 win at Almeria.
Messi hurt a muscle in his right thigh after scoring in Barcelona's victory.
It is Messi's second leg injury this season. He missed the second game of the season after bruising his left thigh and was ruled out of several games at the end of last season with a right hamstring pull.
Besides the Celtic match, Messi is set to miss Argentina's games against Peru on Oct. 11 and Uruguay on Oct. 15 as well as two Spanish league games against Valladolid and Osasuna.Suggest a correction