Barcelona's Leo Messi walks after being replaced during their Spanish First Division soccer match against Almeria at Juegos Mediterraneos stadium in Almeria September 28, 2013. [Photo/Agencies]

BARCELONA -- Lionel Messi injured a leg for the second time this season in Barcelona's 2-0 win at Almeria on Sept 28, leaving him doubtful for next week's Champions League match at Glasgow Celtic.

The club said on Twitter that "Messi has a muscle injury in his right thigh" and he will undergo more tests Sunday.

The four-time FIFA Player of the Year gave Barcelona a 1-0 lead in the 21st minute with his eighth league goal this season and 11th overall. Eight minutes later, Messi asked coach Gerardo Martino to take him out after making a long sprint to pressure the goalkeeper.

Messi walked off the field and was replaced by Xavi Hernandez. Messi spent the rest of the match on the bench and watched Adriano score in the second half.

Messi missed Barcelona's second league game this season after bruising his left thigh. He missed several games at the end of last season with a right hamstring pull.