The former English defender believes the Gunners fans will be gutted they failed to sign the Ukrainian.
Arsenal were on the verge of signing the Ukrainian before Chelsea hijacked the deal, paying around £99 million for the player.
The Gunners subsequently signed Leandro Trossard from Brighton and Mudryk made his Chelsea debut at Anfield on Saturday.
The Ukraine international was impressive in the 0-0 draw and Ferdinand noted the winger will be a “frightening proposition” for Premier League full-backs.
“We’ve all seen the clips of him and that explosive pace. But what I liked about him today is we saw soft feet on him and a good weight of pass too.
“He was making good decisions in the final third and was showing calmness while running at speed. Those elements make him a frightening proposition for full-backs when he gets into full flow.
“This is only his first minutes in a month or so. Who knows what he’s going to be producing after this but it’s exciting for Chelsea fans.
“I’m sure there will be Arsenal fans sitting there going, ‘oh my days, how did we let that one go?'”