Collingwood's inaugural big league captain, Bill Strickland, was recruited from Carlton. That was in 1897. The two clubs were on companionable terms until a torrid grand final in 1910, won by the Magpies. More than 100 years later, the feeling has not abated and still animates the game's oldest extant rivalry. Of the few players who have moved between the clubs since, none was at once as high-profile, accomplished and close to his prime as Dale Thomas, who suits up for the Blues against the Magpies for the first time on Friday night.

"He'll struggle," said Ray Byrne, a nuggety back pocket who crossed the Fitzroy line from Carlton to Collingwood in mid-1978 and whose ultimate distinction was to play an aggregate of four grand finals for the two clubs and win none. "Daisy was there so long. He played in a premiership. I struggled. I'd grown up with Trevor Keogh and Roddy Ashman and them. That was very hard. He wouldn't be human if he wasn't thinking about it."

Byrne cherished his seven years at Collingwood before moving to Geelong for a last fling. "The day we played Collingwood, seriously, I was a mess," he said. "I didn't get a kick. They were very good to me, Collingwood. I reckon he'll find it really hard. But they're different today. Professionals."

Enmity endures, but protocols change. After five years as a fringe player for Carlton, Harry Sullivan rang Collingwood about a game in 1955 and was offered one. When Sullivan told Carlton's chairman of selectors that he wanted to move, he replied: "Off you go."

Sullivan's first game for Collingwood was as a forward, against Footscray great Ted Whitten, and ended badly; he was dropped. Re-tooled in the reserves as a full-back, he went on to play there in the Magpies' iconic 1958 premiership team, andfor Victoria that year.

Of his return games against the Blues, Sullivan, now 82, remembers only stately good grace. One was against the teenaged Serge Silvagni, another against supposedly gruff Wes Lofts, who wished Sullivan good luck not just on his own behalf, but also the Carlton treasurer's!

The years came and went, and the score that can never be settled, mounted. Byrne remembers that Carlton kept count, more so than Collingwood. "The committee loved to play and beat Collingwood," he said. "At Collingwood, that was nothing new. Everyone wanted to have a crack at them."

Traffic between the clubs was spasmodic. There was no "keep off the grass" deal, says Collingwood president Eddie McGuire. It was just that the clubs were as different as states, and the border formalities were not worth the trouble.

Goalkicking great Peter McKenna spent a year at Carlton after finishing at Collingwood, but ached to have to play against the Magpies and regretted the dalliance. Mick McGuane had a disastrous three-game career with the Blues post-Collingwood. He now makes light of it. "You taught me the Broady way," he says to McGuire. "You said, go and rob them. I did: 70 grand a game."

Heath Scotland has parlayed 53 games for Collingwood into 200 more for the Blues, including a best-and-fairest. No one has made the leap with more success and less fuss.

But most of the rest were either peripheral or past it. Thomas was different. He had arrived at Collingwood when it was at a low ebb, and club and fans had fastened onto him as an appealing figure around whom they could rally. For a while, he personified the club. Thommo's Team 13 made him king of the kids. If not for injury and free agency, Thomas might have been a Pie for good.

But the landscape changed, and both parties recalibrated. Ultimately, Thomas had Collingwood's blessing to move, but there was no "off you go". The way the system works, Collingwood wanted Carlton to pay a price that guaranteed the Magpies a first-round pick as compensation. At length, Carlton did.

Until Mick Malthouse, no one had coached both clubs. But Gavin Brown has served on each coaching panel. The Collingwood great found that the rivals had much in common, and with every other club, in their day-to-day affairs. "They have to be; they're all in the same business," he said. "But culturally, there's subtle differences." These were played up when they met one another, though not by the clubs. "It builds itself up," said Brown. "It's automatic."

Symbolism matters as much as substance. When Byrne wore a Carlton jumper to Collingwood training one night, he was frowned upon. When Ang Christou wore a Collingwood No 35 jumper as his casual attire to a Carlton Under 19 match, he was sent home.

McGuire said it was only ever about the jumper, which was why he bore no grudge against Thomas personally, understood that he took an offer few would refuse and texted best wishes to him before round one this year. "I won't be calling for his head any more than Marc Murphy's," McGuire said. "I'm not raining on the parade. Obviously, we will be giving plenty, and I'm sure the supporters will as well. But it's all part of the footy pantomime."

McGuire said he became aware of "hate" merchandise when Malthouse first went up against Collingwood last year, and stomped on it. "Yes, we're playing for sheep stations in the football vernacular," he said. "But we never want it to get like Celtic and Rangers. It's only ever a Tattslotto ticket."

Fans have the luxury of not knowing players or clubs intimately, and so can ascribe to them any characteristic they like, and barrack in any way they please. Shane Collins, a barrister and ardent Pies supporter, says he understands that Thomas's decision was fiscal. "Notwithstanding, at the end of the day, do I want Daisy pushing up daisies (metaphorically speaking) when I sight him in a Blues jumper? Yes, yes and yes!" he said.

"I was at the 1970 grand final. I still enjoy the now decidedly cold revenge of beating Carlton whenever. Friday night's victory shall be all the more enjoyable knowing Mad Mick sacked the Blues' best forward and replaced him with an injury-prone wingman."

Variations on that sentiment abound.Though it is 25 years since Magpies and Blues last met in a final, all aver that the rivalry is as intense as ever. "I think so," said Byrne. "Carlton/Collingwood's always been the same, and Mick going over there has thrown a few more logs on the fire." Admitted McGuire, by now pacing the Westpac Centre floor: "I'll be antsy all day Friday."

This is the historical hornet's nest that Thomas has stirred up and now must throw himself into. He might get a handshake from an old teammate, but should not expect greetings from the treasurer. It will be a sterling test of character as well as football. Brown, now observing from a safe distance at North Melbourne, thinks he will handle it. "He'll be a bit toey," he said. "But, knowing Daisy, I couldn't imagine it will faze him too much."

McGuire hopes Thomas is fazed just enough to do as he did for eight years, contribute to another Collingwood win. Whatever happens, this year and for the next five, McGuire envisages Thomas on one more ritual crossing of the Fitzroy line. "When his time finishes over there, he'll come back," he said, "and I'll make sure he's a life member."

The Big Switch

Players who have represented both Carlton and Collingwood in the past 50 years.

Peter McKenna: 180 matches for Collingwood from 1965-1975, 11 for Carlton in 1977. Left when 29.

Ray Byrne: 81 for Carlton from 1973-mid 1978, 121 for Collingwood from mid 1978-1983. Left when 24.

Russell Ohlsen: 47 for Carlton from 1975-78, 50 for Collingwood from 1979-1981. Left when 22.

Mick McGuane: 152 for Collingwood from 1987-1996, 3 for Carlton in 1997. Left when 28.

Barry Mitchell: 13 for Collingwood in 1993, 38 for Carlton from 1994-1996. Left when 27.

Trent Hotton: 17 for Collingwood from 1994-1996, 61 for Carlton from 2000-2002. Left when 22.

Heath Scotland: 53 for Collingwood from 1999-2003; 214 for Carlton since 2004. Left when 23.

Cameron Cloke: 21 for Collingwood from 2004-2006, 36 for Carlton from 2007-2009. Left when 23.

Chris Bryan: 16 for Carlton from 2005-2006, 30 for Collingwood from 2007-2009. Left when 24.

Jordan Russell: 116 for Carlton from 2005-2012, 9 for Collingwood in 2013. Left when 25.

Dale Thomas: 157 for Collingwood from 2006-2013, 6 for Carlton in 2014. Now 26.

Compiled by JESSE HOGAN