Marsh said conversations in the lead-up to receiving the news on Tuesday night had pointed towards the 29-year-old remaining in his adopted state.

``We'd had some discussions with Cos, and they were all very positive in terms of him staying, so it did come as a bit of a shock to me and our list management group,'' Marsh said yesterday.

``The last conversation we had with him was very positive and we had no indication that he was going to leave, so that was a bit disappointing, but you move on.

``It's thrown us out a little bit, but we've got some work to do in the next couple of weeks.''

But Marsh said he would be ``interested'' to see how Cosgrove goes again with the state that once sacked him as it felt it was unable to help him reach his potential.

His weight also seemed to be an issue, a problem that no longer seems to be a concern after he lost 16 kilograms before the start of this summer.

Marsh said all previous coach Tim Coyle cared about from Cosgrove was runs.

``He was sacked by South Australia and (SA high performance general manager) Jamie Cox, and he's obviously now forgiven him for whatever he did.

``No doubt the same pressure will be there when he gets there, so it will be interesting to see how he goes.''

The left-hander's defection means the Tigers have lost a player with 129 first class and 122 one-day matches of experience.

He played 39 Sheffield Shield matches for Tasmania and made 2514 runs at an average of 40.54, including four centuries and 16 half-centuries, playing in Shield titles in 2010-11 (when he hit the winning runs) and 2012-13.

While still on the hunt for a batsman who can do the job against the red ball and the white ball, someone to help guide youngsters Jordan Silk, Beau Webster and Sean Willis is now a must for Tasmania.

``We understand that they need to bat with some experience around them,'' Marsh said.

``So the decision we make going forward is do we go for another really experienced player or someone who is in their mid-20s who is looking for another crack at it from another state.''

The Tigers also have to deal with Ed Cowan, Xavier Doherty and Ben Hilfenhaus returning to their payroll after losing their Cricket Australia contracts.