Gunners boss Arsene Wenger has a crisis with his forwards after stand-in Nicklas Bendtner sprained an ankle scoring in Wednesday’s 2-0 win over Cardiff.

He will be out for at least six weeks and first-choice Olivier Giroud is also missing due to an ankle injury.

Costa, 25, has a £32m buyout clause in his Atletico Madrid contract and it would be a huge investment for the north Londoners following the £42.5m purchase of Mesut Ozil from Real Madrid in the summer.

Brazil-born striker Costa – who last year declared he wants to play for Spain – has scored a staggering 19 goals in just 17 La Liga appearances this season.

Starsport understands Chelsea are also keen on Costa, and were planning to make their move in the summer.

Blues boss Jose Mourinho maintains he will not sign a striker during this transfer window.