Sergio Roberto was diagnosed with a right thigh injury following tests on Thursday. "His availability will be decided by the length of his rehabilitation," the club said in a statement. The 26-year-old Brazilian made 16 appearances this season, scoring twice. Roberto joined City from Corinthians in July 2014 after making 170 appearances for his previous club across two spells. He helped City to the Premier League title in his first season and was named PFA Player of the Year. However, he missed much of last season after breaking his leg in a match against Stoke City in April 2015. Before joining City, Roberto played for Flamengo, Palmeiras and Santos. He has also represented Brazil at under-20 level. City are without several key players through injury as they look to finish as high as possible in the table. Defender Gaël Clichy (ankle), midfielder Yaya Toure (knee) and striker Edin Džeko (knee) have all been ruled out for several weeks. Midfielder David Silva (achilles) and forward Mario Balotelli (knee) are also doubts to face Liverpool. Forward Nikica Jelavic is expected to return from a knee injury soon that has kept him out since early September.