"He's a special character isn't he?," coach Rennie said. "When you're under pressure you need your experienced players to stand up and I thought he was sensational last week. I think New Zealand's missed a beat there, the fact that this guy is leaving. If he had had a chance of wearing the black jersey last year he may well have stayed. He's a big loss for us. He's a quality man, he has a massive influence on this group. He's demanding, he's made real shifts in his game. We'll miss him big time."
Clarke was on the fringe of the All Blacks last year. The national team's medical staff kept an eye on his knee - he played in last year's final despite the problem - which meant he was on Steve Hansen's radar, and there is no doubt he would have been an All Black this year ahead of Hurricane Jeremy Thrush if he wasn't leaving.
Clarke, also the captain of Taranaki, began his career at the Crusaders in 2006 before finding his way to the Chiefs via the Hurricanes. He has worn the black, red and yellow for five seasons, captaining the team for the past two alongside Messam.
Prop Toby Smith, who had a strong finish to the season, is also leaving, as is halfback Brendon Leonard.
Rennie said he had signed 25 of 28 players for next season. He is leaving a spot open for Sonny Bill Williams but the midfielder is expected to stay at the Sydney Roosters for another year.
Mike Fitzgerald and Ross Filipo, who has recently been concentrating on No8, could be candidates as Clarke's replacement. Rennie will also be keeping a watch on the ITM Cup for young talent. Either way, the man known as Weka leaves big boots to fill.
Chiefs v Brumbies
Waikato Stadium, 7.35 tonight
Chiefs: Gareth Anscombe, Masaga/Robinson, Charlie Ngatai, Andrew Horrell, Asaeli Tikoirotuma, Aaron Cruden, T. Kerr-Barlow, Matt Vant Leven, Tanerau Latimer, Liam Messam, Brodie Retallick, Craig Clarke (c), Ben Tameifuna, Hika Elliot, Toby Smith
Reserves: Rhys Marshall, Ben Afeaki, Michael Fitzgerald, Sam Cane, Augustine Pulu, Bundee Aki, Robbie Robinson/Patrick Osborne.
Brumbies: Jesse Mogg, Henry Speight, Tevita Kuridrani, Christian Lealiifano, Clyde Rathbone, Matt Toomua, Nic White, Ben Mowen (c), George Smith, Peter Kimlin, Sam Carter, Scott Fardy, Ben Alexander, Stephen Moore, Scott Sio
Reserves: Siliva Siliva, Ruan Smith, Fotu Auelua, Colby Faingaa, Ian Prior, Andrew Smith, Joe Tomane.