"It's a bit of a shame," he said.
"I think duck shooting probably had an effect. But I think they'll be all right.
"We'll have a pretty intense training to make up for that game stuff."
This Saturday's game, to be held at Whanganui High School, shapes as an intriguing contest.
In their inaugural season, Metro failed to beat Massey White, however the Wanganui side look to be in with the better chance this time around.
Two weeks ago Metro beat Feilding 24-10, just a week after Massey went down to the third-placed Feilding side.
"They're definitely beatable. We need to just keep doing what we're doing, basically, but just do it well," Gibson said.
"Everyone's been training well and they know how important this game is."
It was important to get on top of the table early on in the first round to be in prime position to host home finals, he said.
A Metro loss to Massey White would see the two sides switch places at the top of the ladder.
"It's not do-or-die but it's really important to come out on top of the group," he said.
Gibson said Metro will take a settled squad into the game.
St Johns Whanganui Metro Colts vs Massey White kicks off at 1pm at Whanganui High School.