The hit man, who scored five goals in 11 appearances for the Blues whilst on loan from Manchester City last season, returned to Eastlands when his loan spell ended after the final game of last season.
It was thought that any interest that David Moyes may have had in the striker ended there, but Jo returned to Finch Farm yesterday to undergo fitness tests.
And he has subsequently joined up with the squad as they undergo some pre season training in Scotland.
It's well documented that Jo had a miserable time at Man City after signing for £18 million from CSKA Moscow last summer.
And with the arrival of Roque Santa Cruz and the imminent signing of Carlos Tevez, depending upon which rag you believe, Jo will be well down the pecking order.
And where exactly does the phrase 'pecking order' come from?
In this isntance it conjours up images of a Man City players all lined up in front of a blushing Mark Hughes, head slightly cocked, awaiting a little kiss on the cheek from each of his men.
Football eh? Crazy!
Anyway, the most remarkable thing about this story is that at no point has a swap deal for Joleon Lescott been mentioned...it's only a matter of time though!