Win and the Steamers will likely have a home semifinal - lose and they could miss the playoffs all together.
Harris says it is always good to be back in the blue and gold.
"It is tough playing Waikato. They are a pretty good side. They always think we are the smaller brother or whatever you want to call it. Last time I played against Waikato we got pumped on Tauranga Domain [43-10 in 2015]," he said.
"I will be making sure when I am putting my boots on that I will be thinking about that game, and put a bit more venom out there when I pull the jersey on at 2.30."
Harris said he had tried to keep up with how the Steamers were going but in places like Argentina it was not so easy.
"It is all hard-out soccer there so I was trying to keep up with score updates. The time zone makes it tough so I missed both last games but I got an understanding on Twitter of how we are tracking and what guys are putting their hands up."
Sitting on the sideline is not much fun for any rugby player. After a serious leg injury last year Harris has been unable to get past hookers Dane Coles and Cody Taylor in the pecking order so far.
But he has travelled to South Africa, Argentina, Australia and the home tests as an important component of the squad.
"It is frustrating I guess in any team, let alone the All Blacks. We all strive to be the best we can be and if you get that shot you have to take your chances," Harris said.
"I can't control me playing or not so I just try to work on my gym work, some fitness and things like that, and other things I can do. I just strive to become a better person."
Harris has not given up on winning the number 2 or 16 jersey back, with plenty more international rugby to be played in 2017.
"We are all different athletes and we are trying to be the best we can be. I do everything I can do to improve myself. I am not too sure of the differences between us, as we are all great scrummagers and throwers and we are all pretty fast out wide.
"There is not too much between us in that aspect so it just depends on the team we are playing and who gets a crack I guess."
Bay of Plenty v Waikato
Tauranga Domain, Saturday, 2.35pm
Curtain raiser: BOP U15 v Waikato U15, 12.30pm
Tickets: www.boprugby.co.nz or www.ticketmaster.co.nz.