Jason Castro down with ankle injury as Gilas bows to Euskadi in tuneup match
Jason Castro will undergo a scan to determine the extent of the suspected Achilles tendon injury. Jerome Ascano

GILAS Pilipinas’ Fiba World Cup preparations suffered a big blow after top guard Jason Castro hurt his ankle in the Nationals' 66-75 loss to Euskadi during their tuneup match on Tuesday in San Sebastian, Spain (Wednesday, Manila time).

Castro, voted one of Asia's best guards during last year's Fiba Asia Men's Championship in Manila, will undergo an MRI on Wednesday to see the extent of what is feared to be an Achilles tendon injury, according to Gilas team manager Aboy Castro.

The Filipinos, who are coming off a winless campaign in a pocket tournament in Antibes, France last weekend, cut the Balkan team's lead to ix points with 1:30 left but ran out of time as they absorbed their fourth straight defeat in their pre-Fiba World Cup buildup.

New naturalized Filipino citizen Andray Blatche led Gilas with 19 points and seven rebounds, while forward Marc Pingris had 10 and nine while battling bigger opponents.

Jimmy Alapag added nine points, three rebounds and two assists while LA Tenorio and Gabe Norwood added seven points apiece.

Gilas returns to action on Thursday to take on Angola, also in San Sebastian.

Follow the writer on Twitter: @richava