Per Mertesacker received his fair share of stick after getting himself sent off for a foul on Diego Costa during Arsenal’s loss to Chelsea at the weekend, but getting trolled by former teammates? He probably didn’t expect that. Emmanuel Frimpong was the culprit in question, unsurprisingly, taking to Instagram to post a picture of Mertesacker and Olivier Giroud with the caption ‘when you’re forced to sit next to someone who ruined your day’. Did Mertesacker ruin Arsenal’s day? Probably - though Frimpong’s hardly in a position to be taking shots at World Cup winners. Meanwhile, Danny Welbeck is in line to return to Gunners training today following a lengthy absence enforced by a knee injury. The 25-year-old is due to make his comeback with the first-team at some point in February, let us know your thoughts in the comments box below.