Having watched Brett Kirk's resurgence upon sighting the AFL finish line, Sydney coach Paul Roos expects nothing less from Brad Johnson when the Swans face the Western Bulldogs.

Over the past month Johnson has been a microcosm of his club, dropping away drastically in form as first illness then injury beset him.

He was one of many Bulldogs strugglers in the 62-point trouncing by Collingwood in the qualifying final on Saturday, before on Monday announcing his retirement, effective at season's end.

But Roos stressed that Johnson was still capable of producing in Saturday night's semi-final at the MCG, potentially the final juncture of a 17-year career.

There are certain parallels with the final year of Swans skipper Kirk, who seemed to be running on empty until after he announced his retirement, slowly gathering momentum to put in a handful of excellent displays in the final weeks of the season and Sunday's elimination final victory over Carlton.

"It's probably a little bit like Kirky," said Roos.

"People were criticising Kirky in the middle of the year, and champion players find a way. He's a champion player and he'll bounce back and he's one who we really need to watch on Saturday night.

"You can tell Rocket ('Dogs coach Rodney Eade) has got a lot of confidence in Brad Johnson, and if I was coaching him I'd have a lot of confidence in him as well, because he's a genuine champion of the game and they always find a way to get the job done."

When asked whether he would pick Johnson to play if he were coaching the Bulldogs, Roos did not hesitate.

"Absolutely, no question," he said.

As for where Johnson ranked as a player, Roos placed him very highly indeed.

"He's been an exceptional player for the Bulldogs, he's been one of the genuine stars of the competition over the last 15-16 years," he said.

"(There's) his longevity and also he's been a terrific role model and he's one of those guys who've been universally respected by his opponents and his teammates."

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