Originally scheduled for a 4.30pm local-time kick-off, the game will now commence at 7pm. FFA announced the change on Friday following several days of monitoring the weather and consulting with the Adelaide club.
There is a forecast top temperature of 40 degrees celsius for Adelaide on Sunday and the problem for match-day organisers was that the A-League game was the second match of a double-header, with a W-League game between the same two clubs preceding it.
The W-League game, originally scheduled for a 1.30pm kick-off, was re-scheduled for 4pm.
Even at 7pm there will still be some bite left in the conditions, but Adelaide football manager Ante Kovacevic said the players were doing all of the right things in the lead-up.
"It's a multi-day process for the players, leading up to the game," Kovacevic said. "It's very important what you do in the 48 hours before the game, to ensure the players keep cool, stay out of the sun, increase their water intake and increase their salt intake at meals as well, to guard against cramping.
"They've been training earlier as well this week, about a 9.30am start, and the sessions have been a bit shorter and sharper to make sure we're out of there before the heat sets in.
"And then obviously it's important on match day as well to stay out of the heat as much as you can in the hours leading up to the game.
"If necessary, it becomes a pre-match, halftime, post-match process when you play in the heat. It's all about keeping cool, using ice baths, ice vests, having the air conditioning running in the change-rooms to keep the body temperatures down.
The W-League players would obviously be taking similar precautions, particularly as their match starts earlier.
FFA uses the Wet Bulb Globe Temperature index as its means of deciding whether games should be delayed or even postponed.
The media release issued by FFA on Friday read, in part: "The WBGT forecast for Sunday is currently above 28 degrees at 1.30pm (ACDT) when the Westfield W-League match was due to kick off, dropping below the regulated threshold by 4pm (ACDT)."
A-League boss Damien de Bohun was quoted in the release, saying: "With the forecast WBGT due to be above the regulated threshold for the duration of the scheduled Westfield W-League match we have decided to move both games back two and a half hours to allow both matches to be played under safe conditions that fall within the parameters of the Heat Policy.
"FFA will continue to monitor the situation, keep relevant stakeholders updated and will consider the need for drinks breaks or further deferment of the matches on Sunday."
The Adelaide and Perth clubs obviously welcomed the delaying of the kick-offs, not only for the safety of the players in the heat but also because playing in extreme heat inevitably affects the quality of matches as spectacles. Adelaide, in particular, likes to play a fast-paced game.
There is a continuing debate over whether the WBGT index should be used as a an absolute decision-maker or only as a guide.
Earlier this week, Darren Burgess, currently the high performance manager at Port Adelaide AFL club but also with enormous experience working in football, said he believed it should only be used as a guide.
Burgess said there should be flexibility for match officials to be able to make common-sense decisions according to the conditions on the day.
Kovacevic agrees with Burgess that the WBGT should only be used as a guide, although he and the Adelaide club are obviously happy FFA made an early call on delaying Sunday's games.