Regardless of the future, the Phoenix will want to end this season on a high.
"We finished the back end of last season on a bit of a downward spiral," said Buckingham.
"This season is actually finishing on a positive in terms of results and performances.
"[We've prepared] the same way we have all the way through the season and, in particular, the last three or four weeks, in which we've not only got some results, but also the performances have been really pleasing.
"It's important we go to Brisbane and follow that up, and finish with a win," he said.
Last season, the Phoenix lost their last four games. This time around, they'll be unbeaten through their last four, if they avoid defeat tonight.
It's an impressive record, given three of those four outings are against sides that will likely fill the top three spots on the ladder.
Greenacre and Buckingham have close to a full squad to choose from, with only Matthew Ridenton and Dylan Fox ruled out with injury. Veteran striker Shane Smeltz has also departed to take up a contract in Indonesia.
"The players have been really good this week," said Buckingham.
"It's easy to switch off, once you know you're mathematically out of the playoffs, but they've approached the week well and we're really looking forward to the weekend," he added.
Brisbane enter the final round of the regular season in fourth place, but could grab third, if they beat or draw with the Phoenix, and Melbourne City (who are currently third) lose to Perth later tonight.
Both clashes between Wellington and Brisbane this season have been won by the away side, with the Phoenix grabbing just a second-ever win in 15 visits to Suncorp, when the sides clashed there seven weeks ago.