The 30-year-old centre-half became the third Wednesday signing of the January transfer window after those of Jordan Storey and Tyreece John-Jules.
But after a public falling-out with his Blues boss Lee Bowyer, what are Wednesday fans to expect from Dean?
We spoke to BirminghamWorld football writer Ben Ramsdale to get the inside line on the six-foot-three defender.
It's a surprise to many that Dean is being allowed to move on. What's been the issue between him and Bowyer?
It's a weird one. Some would say there is obviously a deep-rooted issue there where others would argue Dean has simply been made a bit of a scapegoat.
When [Aitor] Karanka first got the boot, Dean revitalised his career at Blues and was a key part in them retaining their Championship status that year under Bowyer.
He's has a mistake in him though, even during that purple patch and that's something that continued into this campaign.
With that said, was he making any more errors than other members of the playing squad? Probably not. But none were ever dropped as quickly as Dean was.
Whether he was being made an example out of because he was the captain or something more, we'll never really know but it's a relationship that certainly now seems beyond repair.
How would you describe him as a player?
He's certainly a leader. He wasn't made club captain at Birmingham City because of his quiet nature.
He's very vocal on the pitch and you'd probably describe him as a bit of a no nonsense old fashioned centre-back.
I've never heard word of him being 'toxic' in the dressing room or anything of the sort. He's the club captain, he wouldn't have ever been given that honour if he wasn't well respected by his peers.
Delving into my not-so vast Sheffield Wednesday knowledge, maybe a similar style to Miguel Llera?
He's been in the Championship a while - how would you expect him to get on at Wednesday?
There's a decent central defender in there, there's no doubt about it. He was never going to be the best player in the Championship but I think he does have the potential to be one of the better players in League One.
A Wednesday supporting friend of mine tells me the Owls need a leader. Well, you should have one in Dean.
What else can you tell us about Dean?
Bowyer was a bit cryptic when discussing Dean and certain other members of the playing staff. He said he demands certain things of his players and that's why he's being allowed to move on.
It doesn't take a genius to work out that the defender obviously wasn't meeting Bowyer's expectations in some way. It seems the two were never going to meet eye-to-eye and that happens in football sometimes.
At 30-years-old, theoretically, Dean is at the peak of his career as a central defender and he now has a chance to go out there and prove the doubters wrong. That can only work in Wednesday's favour.
Overall I think it's a move that suits both parties and I do think he'll have a successful spell at Hillsborough.