Coles suffered rib cartilage damage during the Super Rugby playoffs and while he started the final for the Wellington Hurricanes, he had to be replaced during the 20-3 victory over the Lions with a recurrence of pain in the affected area.
The 29-year-old had not been named in the matchday squad for the clash at Sydney's Olympic Stadium, but with Harris' rupturing his anterior cruciate ligament at training on Thursday, coach Steve Hansen had no choice but to bring Coles onto the bench.
"The reason we didn't play him was because of the type of injury he's got," Hansen told reporters in Sydney of being forced to bring Coles into the side.
"They tend to niggle on so we thought if we could give him an extra week we wouldn't have that problem.
"But now we don't have that luxury so out he goes when the time comes."
Hansen added that Coles had only travelled with the side to Australia to receive treatment from the All Blacks medical staff, but would be expected to play "for 80 minutes" if Codie Taylor, who will now start, gets injured.
Harris was likely to be out for the rest of the season and Hansen said they would not make a decision on his replacement until they returned to New Zealand on Sunday.
After Saturday's clash, the two sides head to Wellington for the second match of the southern hemisphere championship on Aug. 27.
Both games double as matches for the Bledisloe Cup.
New Zealand have held the symbol of trans-Tasman supremacy since 2003.
(Reporting by Greg Stutchbury in Wellington; Editing by Amlan Chakraborty)
