As the previously indestructible Aaron Cruden recovers from his broken thumb, the Chiefs must be wary of placing too much more pressure on the team's other iron man, Liam Messam.
Loose forward Messam, the team's co-captain with Cruden, has, like the first-five, played in every minute of every game for the team this season.
Cruden, who does not need surgery but will still be out for six weeks at least, is the slippery little linchpin on which the team's backline relies so much, but Messam is the muscular driving force which binds the whole operation together. His importance to the team has just risen further.
All Blacks flanker Messam is the only forward among the five New Zealand franchises to have played every minute for his team this season. Four other backs have done so and not surprisingly they are also among their team's most important players - Ben Smith and Malakai Fekitoa for the Highlanders, Charles Piutau for the Blues and Conrad Smith for the Hurricanes.
Ryan Crotty, who led the Crusaders to their 28-7 win over the Lions in Johannesburg at the weekend, has played all but eight minutes.
The workload on Messam, who is likely to get plenty of game time for the All Blacks during the three-test series against England in June, must be managed carefully - and that's a real juggling act for Super Rugby coaches.
Blues coach Sir John Kirwan has talked about having the courage to rest players such as skipper Luke Braid. He named Braid on the reserves bench for the match against the Brumbies in Canberra where the team put in their most disappointing performance of the season in the 26-9 defeat. Braid played the final 22 minutes but the tactically naive Blues could have done with the hard-working loose forward's leadership for the entire match.
Dave Rennie could have been tempted to rest Messam for Saturday's match against the Rebels in Hamilton, but Cruden's injury and the team's performances in South Africa, where they gave up big leads to the Bulls and Cheetahs before scrambling to draw - after losing to the Force in Perth - will complicate things.
Coaches for years have talked about there being no easy games in this competition but this season is shaping up to be one of the most even yet. The Chiefs, third overall on 20 competition points, lead the New Zealand conference by four points from the Hurricanes and Blues. The Highlanders are a point behind, with the Crusaders not too far away on 13 points. The Rebels match should be a victory but the Chiefs can't afford to leak more competition points.
Messam has form in terms of durability. Before the season kicked off he had missed only two games in the last five seasons of Super Rugby, so the comments from forwards coach Tom Coventry at the start of last month about the workload of his top players are even more pertinent now.
"Success comes in having your leaders play consistently," he said. "But we're conscious that we can't continue to use them for every match, and that's something we're going to have to consider over the next six or seven months."