Arsenal manager Arsene Wenger has claimed that he is unsure how long Aaron Ramsey will be on the sidelines for after picking up an injury against Watford on Tuesday night.

The midfielder was substituted in the second half shortly after Watford raced to a 2-0 lead thanks to goals from Younes Kaboul and Troy Deeney inside the first 15 minutes at the Emirates.

Alex Oxlade-Chamberlain was also spotted limping in the final stages of the game, but Wenger expects the England international to be fit for Saturday's trip to Chelsea.

"[Ramsey has] a calf strain," The Metro quotes Wenger as saying. "I don't know how long he will be out for, but it's a calf strain.

"I don't think [Oxlade-Chamberlain is a doubt]. I think he should be alright."

Overall, it was a disappointing night for Arsenal as they were beaten 2-1 on home soil.