Thompson, who had a breakthrough year at fullback in 2013, was studying footage of Cameron and Patton when his match preparation was thrown a late curveball.
First choice ruckman Tom Nicholls (calf) pulled up sore from the team's final training session and was ruled out.
With Zac Smith in the late stages of overcoming a full knee reconstruction, and Charlie Dixon (groin) making his return through the reserves on Saturday, the Suns' cupboard for ruckmen was bare.
Thompson played there as a junior, but admitted it was "years" since he had taken on any more than a pinch-hit role in the position.
"I just finished doing my edits on Patton and Cameron and then big (midfield coach) Matty Primus walked in, put his head down and I got told the good news," Thompson laughed.
"I chopped out a bit last week and I just had to play my role, compete, and that's it. I wasn't overly stressed."
The 200cm Thompson was clearly beaten in the hitouts by Jonathan Giles (51-27), but competed well enough to allow the brilliant Suns midfield to dominate the clearances (44-36).
Suns coach Guy McKenna admitted post-match he had asked a lot of the 23-year-old, particularly after a pre-season limited by a hip arthroscopy.
"To throw him into the ruck and run like he did all day was a terrific effort," McKenna said.
But neither McKenna or Thompson want it to become a regular option.
Nicholls is expected to be available next week, as is Dixon who was promising in his return at NEAFL level.
"As the day went on, I started remembering back to the old junior days of playing ruck and what to do," Thompson said.
"Hopefully we'll get our talls back on the track and I can settle myself back in defence for the rest of the season.
"I'll be on their backs making sure they do all their recovery this week," he joked.
