ROME, April 20 (Reuters) - AS Roma striker Francesco Totti could miss the start of next season after undergoing a knee operation, the club doctor said on Sunday. The 31-year-old, troubled by niggles all season, suffered a cruciate ligament injury in title-chasing Roma's 1-1 draw with Livorno on Saturday. 'Professor Pierpaolo Mariani will perform a surgical operation to reconstruct the anterior cruciate ligament, which will take place in the afternoon,' Roma club doctor Mario Brozzi said in a statement. Brozzi also told reporters: 'In the past Roma have dealt with these kinds of injuries. We remember in the cases of Emerson and (Eusebio) Di Francesco they returned to action after four months.' A similar recovery time for Totti would mean he would be back in August but would miss most of pre-season training. Some Italian media reports have speculated Totti, who broke his leg in 2006, could be out for up to six months. 'I am a bit scared because I heard a crack,' Totti told reporters as he arrived at the club clinic on Sunday. 'I will definitely return stronger than before.' Totti, a World Cup winner with Italy in 2006, has retired from international football so would have missed Euro 2008 in any case. Second-placed Roma are battling champions Inter Milan in the race for the Serie A title. Coach Luciano Spalletti normally plays with only one striker and Montenegro's Mirko Vucinic, who scored on Saturday, looks poised to fill in for Totti in their remaining four league games. Roma, the subject of a possible takeover bid, are also in the semi-finals of the Italian Cup.