The Heat took 96 minutes to complete their bowling innings against the Scorchers, six minutes outside the 90-minute limit imposed by the tournament's directors.
The Heat are likely to contest any possible suspension, given there were a number of stoppages for third umpire decisions and a concussion check for Perth batsman Sam Whiteman.
The Heat were previously fined when they exceeded their 90-minute limit against Hobart at the Gabba on December 30 by five-and-a-half minutes. Any second sanction against a team includes the compulsory one-game suspension of the captain.
The Scorchers have replaced the Heat at the top of the BBL standings following Wednesday's victory and with only two games remaining for Brisbane before the finals, wins are vital.
The loss of big-hitter McCullum for their clash against the Melbourne Stars on January 17 would take on even more meaning after the absence of Chris Lynn was felt in Wednesday's loss to the Scorchers.
Perth quick Andrew Tye (4-22) claimed a hat-trick to wrap up the win, with only Alex Ross (39) keeping the Heat in the contest as they were all out for 129 in front of a new domestic-record crowd at the Gabba of 34,677. Without the tournament's leading run-scorer Lynn due to Australian selection, the Heat fell to their to their worst powerplay score of the season - 3-41. And after Mitchell Johnson (2-25) tore through the top order with an early wicket-maiden, they never recovered.
McCullum himself could only muster 15 before he became one of three men to be caught by Ashton Agar, who also went for just 14 with the ball from his four overs.
Earlier, Michael Klinger had carried the Scorchers with an eventful 81. Klinger hit eight of the Scorchers' 11 boundaries in his 54-ball knock, which included two sixes.
However, he should have been dismissed when he was on 54 when he gloved a Ben Cutting bouncer through to wicketkeeper Jimmy Peirson, only for it to be ruled a wide.
He was also caught in front of the sightscreen by Joe Burns when he fought off teammate Brendon McCullum for an over-the-shoulder catch, only for him to then run it over the rope.
Klinger, the leading run-scorer in the history of the competition, was eventually dismissed when caught by Nathan Reardon on the long-on boundary in the 19th over.
Reardon immediately claimed the catch, however Klinger refused to walk when he believed Reardon's heel may have come in contact with the rope. Replays proved inconclusive and Klinger, the only Scorchers batsman to top 20, was visibly unhappy as he returned to the team's dugout.
- news.com.au/AAP
