"I looked at Adam's time that he's been playing and it's trying to manage those two guys efficiently so we're getting the very best out of them," said Kearney.
Mannering's injury opened the door for Papali'i to impress on the left-edge in the round one win over the Rabbitohs, and the 19-year-old recently returned earlier than expected from a knee injury to give Kearney greater flexibility around the make-up of the back-row.
With Papali'i and right side second-rower Tohu Harris able to go the distance each week, Kearney has also been able to utilise Mannering in the No 13 role at different stages, as he also has with injured utility Jazz Tevaga.
"That's the reasoning behind it, getting Simon and playing him as a middle," he said.
"We've got two back-rowers that can play 80 minutes and tonight we didn't have Jazz who's done a wonderful job for us in the middle over the last five or so weeks.
"So that was the reasoning behind it, is just trying to rotate those two older guys, or two more experienced guys, sorry, so that we get the best out of them."
Mannering, one of the toughest players to pull on a Warriors jersey, fractured an eye socket in the win over St George Illawarra and carried the injury into the loss to Melbourne, where he covered for the absence of Harris who missed the match with concussion.
Kearney denied that injury had played into his selection thinking this week, and insisted Mannering was happy with the new arrangement.
The former Warriors and Kiwis captain certainly didn't look hampered as he got through 27 tackles and made 11 runs in a 60 minute contribution in his 285th club appearance.
"One thing I know about Simon, is he's (happy) to do whatever is best for the team," said Kearney.
"He didn't hesitate and when he comes on he takes over from what Adam is doing and keeps it nice and tight and clean in the middle."
Mannering is yet to decide whether he will re-sign with the club for a 14th season next year and it remains to be seen whether Kearney persists in using him in the impact role off the bench in the coming weeks.
Blair said both players understood the logic behind the move but having become accustomed to playing long stints in recent weeks, the Kiwis World Cup leader hinted he was disappointed to have his playing time reduced.
"I've got to do what's best for the team," said Blair.
"I've had a lot of minutes the last eight weeks and now that Simon's back (Kearney) can afford to do those kinds of things.
"Again, not happy, but that's what you've got to do for the team. Whatever's best for the team I'll put my hand up for whatever I have to do."
