ROME, Jan 10 (Reuters) - New AC Milan forward Pato is expected to make his competitive debut against Napoli on Sunday (1930 GMT) as Serie A resumes after the Christmas break and the European champions seek to end a miserable home run.Milan have failed to beat Italian opposition at the San Siro this season and are languishing in mid-table with 18 points, 25 behind leaders Inter Milan, albeit with three games in hand. Club captain Paolo Maldini believes the 18-year-old, who signed from Brazil's Internacional last August but has had to wait until January to become eligible, is ready to help his side turn things around. 'Pato is very strong technically, he can move the ball between his right and left feet and shoot in seconds,' Maldini told reporters. 'The physical power he has for an 18-year-old is impressive'. Kaka should be available after taking a knock to his shoulder in training. But fellow Brazilian Ronaldo looked far from match fit in Tuesday's 2-0 friendly win over the United Arab Emirates on his return from his latest injury setback. With Filippo Inzaghi suffering from a foot injury and a problem with kidney stones, Alberto Gilardino is favourite to be the other part of the strike force. Napoli midfielder Manuele Blasi and striker Marcelo Zalayeta are suspended, although the club are appealing the latter's two-match ban for diving in their 1-1 draw with Torino before Christmas. Unbeaten leaders Inter Milan visit Siena earlier on Sunday (1400 GMT), a ground that will evoke fond memories after they won there 2-1 last season to clinch the Italian title. Midfielders Patrick Vieira and Luis Figo are still not back from long-term injuries, Honduran striker David Suazo is out with a thigh strain and Dejan Stankovic is also a doubt. The champions are expected to be without French midfielder Olivier Dacourt and Argentine defender Walter Samuel for the rest of the season because of knee injuries. AS Roma, who have 36 points from 17 games, seven points behind Inter, take on Atalanta in Bergamo. Third-placed Juventus, 35 points, are aiming for their fourth consecutive league victory on Saturday at Catania.