It leaves Rodney Eade to step in as interim director of football operations while list manager Derek Hine will assist Eade with contracts.
Walsh hinted Thomas would soon put pen to paper and re-sign with the Pies.
"I don’t expect there’s going to be any issue there," Walsh said.
"I don’t think this is going to be drawn out because I know Dale wants to re-contract with the club, and certainly the club wants to re-contract ‘Thommo’."
Walsh said his departure wouldn’t delay the 26-year-old from re-signing.
"Paul Connors, Dale’s manager, has been away for a couple of weeks on holidays and he’s now back," he said.
"Before this situation (leaving Collingwood) arose I spoke to Paul last week and messaged him and said we’d catch up to resume discussions."
Walsh said he would be in regular communication with the football department during a three month ‘notice period’.
"I won’t be involved in the negotiations, that won’t be appropriate," he said.
"Other than (that) I have an agreement in place with the footy club that I will be available for the next period of time for anyone who needs some sort of advice or direction in terms of departmental issues.
"Certainly the salary cap and contracting position will be something I’ll talk to Derek Hine at his behest and the club’s behest."
Darcy Fogarty, Isaac Cumming, Rory Laird and Jordan Dawson deliver a personal tribute to their retiring teammate Taylor Walker.
08:30
Ryan Davis reflects on 2026 AFLW season
Senior Coach Ryan Davis gives an honest assessment of our season, outlines the Club's priorities this off-season and weighs in on the AFLW's evolving fixture debate.
10:18
AFLW Crows Live | Inside the rooms: R12 v Melbourne
Hear from Ebony Marinoff, Marijana Randall and Jess Allan as the Crows season finishes after their clash with Melbourne today at Unley Oval.
04:01
Ryan Davis | Press conference: R12 v Melbourne
Hear from Senior Coach Ryan Davis following our round 12 loss against Melbourne.