The former United defender made the comment following Arsenal’s last-gasp 2-1 victory over Leicester City in the Premier League on Sunday afternoon.
Welbeck scored the winner for the Gunners at the Emirates Stadium in North London in the fifth time of injury time.
Ferdinand was following the match, and he was impressed with the England international striker’s late goal.
Welbeck........i aint even going to start.....happy for Welbz but how @manutd let him go— Rio Ferdinand (@rioferdy5) February 14, 2016
It is easy to criticise United now, especially after Welbeck’s winner against Leicester, but it was clear that the 25-year-old was not going to make it at Old Trafford.
The Englishman is a decent player, but he is not prolific or someone who was going to take United - or any team for that matter - to the next level.
During the 2014-15 campaign, Welbeck scored just four goals and created 29 chances in 25 Premier League appearances for Arsenal.