Arsenal full-back Hector Bellerin has been forced off in the opening stages of his side's crucial Premier League clash against Chelsea.
The Spain international suffered an injury after trying to reach a header in the 13th minute from which compatriot Marcos Alonso gave the Blues the lead.
After receiving lengthy treatment in the six-yard box, Bellerin was replaced by Gabriel at Stamford Bridge.
Arsenal will be hoping the injury suffered by their star is nothing serious, especially as his start to 2017 has already been marred by an ankle knock.
Bellerin had been forced to sit out the 4-0 victory over Swansea in mid-January and only played a single minute of Premier League action since before being restored to the starting XI against Chelsea.
However, his early exit is cause for concern as the Gunners' Champions League clash against Bayern Munich on 15 February looms, with the FA Cup fifth round clash at Sutton United following.
Arsenal entered Saturday's early Premier League kick-off playing catch up to the leaders, Arsene Wenger's men lagging nine points behind the Blues.