Adelaide lose Isaias for a month

Adelaide United will be without key midfielder Isaias for the next month in their run to the A-League finals.

The Spaniard has damaged a lateral ligament in his right knee.

Isaias was a scratching from Adelaide's 3-0 home victory against Brisbane Roar on Saturday, a result which lifted the Reds to second spot - they're now unbeaten in 13 league games.

"Isaias is an important player for us," coach Guillermo Amor said.

"Isaias is a good player with the ball, he wants the the ball, and enjoys the football."

"He's a very good professional but it's not possible to play with his problem in his knee."

Adelaide's next date is an away trip to play Wellington Phoenix next Saturday.