Etzebeth was a notable absentee from the Sharks' side to face the Bulls in Pretoria, with the veteran Springboks lock sustaining an injury during the build-up to the match.
While Plumtree is disappointed not to have the services of his captain, he has provided a positive update on Etzebeth and revealed the nature of his injury.
"He took a knock at training and we decided that it's best not to risk him this week," the Sharks boss said after naming his team.
"We made a pretty early call. He's feeling a lot better by the way, he's been communicating with me and the team.
"I'm not over-concerned about it but I'm pretty sure that if we go through, he'll be available next week and what's the nature of his injury."
Etzebeth missed a large chunk of the Sharks' season with a concussion and Plumtree confirmed that he has suffered yet another head knock but the head coach is still not overly concerned.
"Head knock at training. He is feeling a lot better already," he said.
However, he admits that his absence will certainly be felt on the pitch on Saturday.
"Eben is probably the best lock in the world so it's a big loss but it's a team game and one person doesn't make this team," he continued.
"We've won games without him this year, yes it's disappointing that he's not going to be there but it's exciting for the other players that get the opportunity to play in big games like this."
Meanwhile, Jake White has commented on the absence of Etzebeth saying that he would not be surprised if the Bok second-rower played against his side.
"You say now that Eben is out, I don't know if he is even out, I mean let's be fair, we only see the team that gets here and we can't worry about who said and they said and maybe," he remarked.
"We have got to prepare as though the best team is coming here and I have said before that's probably one of the best Sharks teams that's ever been on paper.
"It reminds me of you Pieter Muller, Andre Joubert, Henry Honiball, Jeremy Thomas, Cabous van der Westhuizen, they were all Springboks and there aren't many Sharks players in that squad now that aren't Springboks.
"In fact, I think there are 15 out of Rassie's 54 are Sharks players so it's not too bad."