Johnston has signed for Coolamon in the Riverina League, with the 2020 Heathcote District League season already called off.
Oliver said he expected Johnston to return to the Cats for 2021 as they aimed to win their first premiership since 2014.
“I'd prefer him not to be going, but he's given us his word that it's only for this shortened season and I'm happy with that,” Oliver told the Bendigo Advertiser.
“(Coolamon) will be stoked. Zeik's a very good player, so to get him halfway through the year is a good get for them.
“If we were playing and he left I'd be upset, but the fact we're not playing makes it easier to take.”
Johnston already has strong experience in the Riverina region after winning three premierships with Temora.
“Zeik loves footy, loves playing footy and it doesn't surprise me that he's teed something up,” Oliver said.
“As soon as the restrictions lifted and we could train in groups of 10 he was expecting us to be training the next night.
“That's how much he loves his footy. There was no point us training when we couldn't guarantee the season.”
Meanwhile, Johnston’s teammates at LBU have taken their minds off footy since the announcement.
“We had a golf day where about 40 of us got together for a hit, but that's about it,” Oliver said.
“We haven't done anything footy-related. The main thing for me now is making sure we get some junior footy up and going.”
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