Sportswriter James Olley described the scene as the England international left the pitch:
Manager Unai Emery discussed the injury after the match, per sportswriters Chris Wheatley and Mattias Karen:
The 27-year-old has been dogged with injuries since making his debut for the Gunners after his arrival from Manchester United in 2014.
However, Welbeck featured in 38 matches in the Premier League and Europe last term, scoring eight goals as he started 17 games as a substitute.
The England international has displayed promising form in the past 12 months, bolstering Arsenal's attack with guile and pace.
However, Welbeck twice suffered setbacks last season, sustaining successive groin and hamstring injuries under former coach Arsene Wenger.
The player's versatility is his most useful weapon, and Emery will have to rely on others as Welbeck recovers.
Alexandre Lacazette and Pierre-Emerick Aubameyang are now the first-choice attackers at the Emirates Stadium, and Emery's thoughts will be about servicing his illustrious pairing.
Welbeck is not a prolific striker, but he is a useful auxiliary option from the bench when Arsenal need to inject additional work rate into their side.