PREVIEW-Soccer-Juve and Roma hit by injury blows in cramped schedule

(Reuters) - Injuries continue to mount in Serie A as Juventus forward Angel Di Maria and AS Roma striker Paulo Dybala became the latest big-name players to be ruled out as clubs battle with a packed fixture schedule.

Like other European leagues, Serie A has had to condense its schedule with the Italian top flight set to shut down for the Qatar World Cup, which begins on Nov. 20, and AC Milan manager Stefano Pioli said muscle injuries had risen by 20 per cent because of the extra pressure.

Some clubs have been hit worse than others.

Table-toppers Napoli, who have been barely affected by injuries, have won five league matches in a row to extend their unbeaten run since the start of the season in both Serie A and in the Champions League.

Luciano Spalletti's side will host Bologna on Sunday after moving to the Champions League knockout stages with two games to spare with another comfortable 4-2 win over Ajax Amsterdam on Tuesday.

Juventus, however, have been hit hard. Midfielder Paul Pogba and forward Federico Chiesa are nearing a return but Di Maria's latest injury still comes at a bad time for Juve, who are eighth in the table with just 13 points, 10 behind leaders Napoli, after a 2-0 loss at AC Milan on Saturday.

Di Maria went off with a hamstring injury as Juve touched a new low in a 2-0 Champions League loss at Maccabi Haifa on Tuesday.

The defeat heaped more pressure on manager Massimiliano Allegri, who ruled out stepping down ahead of their Serie A derby clash with 10th-placed Torino on Saturday.

Roma are sixth in the table and four points behind Napoli but Dybala's injury could also deal a huge blow to Jose Mourinho's side as they travel to bottom team Sampdoria on Monday.

The Argentina international has scored five goals