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."
Hear from Rankine, Nankervis and Mick Godden after the sides win over North in round 10.
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Team Song R10: Kuwarna
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Perfect 10: Every Kuwarna goal from scintillating term
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Cal Ah Chee & Wayne Milera talk guernsey design, culture & their Indigenous heroes
Wayne Milera and Cal Ah Chee share the story behind our 2026 First Nations guernsey while reflecting on the meaning of Sir Doug Nicholls Round and the Indigenous players who inspired them.