"Because we took the very safe measure of having them isolate away from the group, it meant that they missed Monday's and Tuesday's training, so in order to prepare the team as best as possible to go down and play the Crusaders, we felt it was better that we just selected the team in advance of them being cleared."
While the competition has already had matches postponed due to Covid-19, McMillan said he had no thoughts of seeking a postponement since finding out seven of his players had potentially been exposed to the virus.
"We're happy with the team we've put out this week," he said. "There's a number of guys that fell into that boat that may have been considered - obviously there are some experienced guys that have missed out and people are probably wondering why.
"But we needed to give the team that we knew was going to be available the best opportunity to prepare, hence some younger guys have been given an opportunity, and we're entirely happy with that."
The Chiefs look set to cap two more players at Super Rugby level in the match, with prop George Dyer and halfback Cortez Ratima both named to debut from the bench, while Rameka Poihipi and Rivez Reihana also join the reserves. Tom Florence has been bracketed with Laghlan McWhannell on the bench as well, but McMillan said it would be the former who played.
There are several changes in the starting unit, with Emoni Narawa returning at fullback, Anton Lienert-Brown getting his first start of the season in the midfield, Xavier Roe and Bryn Gatland in the No 9 and 10 jerseys, while Kaylum Boshier starts on the blindside as Tupou Vaa'i moves back to lock. Angus Ta'avao also joins the starting squad at tighthead prop, making his 50th appearance in a Chiefs jersey.
"I think it's hugely competitive," McMillan said of the lineup. "It's not too dissimilar to the one we played a final against the Crusaders with last year, and nearly pulled off a miracle."
Crusaders v Chiefs
OrangeTheory Stadium, Christchurch. Saturday March 12, 7.05pm.
Crusaders: Will Jordan, Sevu Reece, Braydon Ennor, David Havili, Leicester Fainga'anuku, Richie Mo'unga, Bryn Hall, Pablo Matera, Tom Christie, Ethan Blackadder, Sam Whitelock, Scott Barrett (c), Fletcher Newell, Codie Taylor, Joe Moody.
Reserves: Brodie McAlister, George Bower, Tamaiti Williams, Mitch Dunshea, Cullen Grace, Te Toiroa Tahuriorangi, Fergus Burke, George Bridge.
Chiefs: Emoni Narawa, Shaun Stevenson, Anton Lienert-Brown, Quinn Tupaea, Etene Nanai-Seturo, Bryn Gatland, Xavier Roe, Pita Gus Sowakula, Sam Cane (c), Kaylum Boshier, Brodie Retallick, Tupou Vaa'i, Angus Ta'avao, Samisoni Taukei'aho, Aidan Ross.
Reserves: Bradley Slater, Ollie Norris, George Dyer, Naitoa Ah Kuoi, Tom Florence, Tom Florence, Cortez Ratima, Rivez Reihana, Rameka Poihipi.