North recently opened preliminary contract discussions with Tarrant in the hope of re-signing him before he becomes an unrestricted free agent at the end of this season.
But AFL.com.au understands that at least two rival clubs have signalled their preparedness to offer Tarrant up to $400,000 a season to lure him away from Arden Street.
Suitors will be keen to see Tarrant play a full 2015 season given his injury-prone history, but he has become a very attractive commodity given the paucity of key defenders in the market and his ability to play in attack.
The Brisbane Lions and Western Bulldogs are two teams actively in the market for key-position players, while Carlton, Fremantle, Adelaide, St Kilda and Geelong are among a raft of other clubs investigating trade and free agency options to shore up their spines.