Bevan's signature comes just 24 hours after the TCA announced it had secured the services of sacked Zimbabwe all-rounder Andy Blignaut.
Chief executive David Johnston said on Friday the TCA was thrilled it had been able to recruit another international cricketer to boost its ranks for next summer.
The 34-year-old Bevan's appointment and transfer to Tasmania is subject to clearance from New South Wales.
Bevan, despite averging 46 for Australia in ODIs and being regarded as one of the finest batsmen in Limited Overs cricket, was dumped last April as a contracted international by Cricket Australia (CA).
Bevan said at the time that he believed he still had plenty to offer and was hoping to change selectors' minds about his involvement in the 2007 World Cup in the West Indies.