The 27-year-old left Pittodrie this summer and joined up with Crewe Alexandra.
But ahead of their Sky Bet League One opener against Cheltenham, Hoban decided to call time on his footballing career.
Earlier this morning, Crewe manager David Artell said: “I had a text off Tommie on the Wednesday before the Cheltenham game, he said he didn’t feel quite right, but it was a pleasant message.
“I gave him a ring and he just told me that he was retiring over the phone and I haven’t seen him since.
“That’s the long and the short of it. The contract situation has been getting sorted over this last week and unfortunately, Tommie has decided to retire.”
It is currently unclear why Hoban has decided to hang up his boots.
A club statement added: “We would like to wish Tommie all the best in his new venture away from football.”