The Prairie Wolf Pack (3-2-0) currently lead the standings with 16 points, ahead of the Ontario Blues (3-1-0) at 15 points, the Rock (2-2-0) at 11 and the Pacific Tyee (1-4-0) at five.
The defending champion Blues are in the driver's seat heading into Saturday's finale against the Rock in St. John's.
The Blues will win the MacTier Cup with a win, tie and even a loss — providing they earn a bonus point and the Rock doesn't.
Bonus points are awarded for losing by less than eight points or scoring four tries.
The Wolf Pack can finish first if the Rock defeat the Blues by less than 50 points but more than seven points (which would deny the Blues a bonus point).
And the Rock can take the title if they beat the Blues by more than 50 points, providing both teams pick up bonus points in the process.
"Mission impossible," Rock coach Simon Blanks said with a chuckle before amending the scenario to "Mission improbable."
"The bottom line is it's highly unlikely that we can win the title," he added. "So we'll just be trying our best to win the game."
Considering the Blues have averaged more than 30 points a game this season, Blanks says it would have to be something like an 80-30 win for the planets to align for his team.
"Which would certainly be a crowd spectacle, there's no doubt about of that, but it's extremely improbable," he added. "There's not too many rugby matches that finish with that type of scoreline."
The Blues defeated the visiting Rock 23-19 when they met in Oakville on Aug. 25 in the season opener.
"Both teams will be considerable changed for this game," said Blues manager Mark Winokur. "We'll probably have added five or six guys and so will they."
To make the Rock's longshot at winning the cup a reality, Blanks' team needs a three-way tie at 16 points atop the standings. If that happens, and the Rock post the requisite winning margin, Blanks' team will win on point difference.
If it is only a two-way tie at the top between the Wolf Pack and the Rock, the title goes to the Wolf Pack due to head-to-head record between the two (by just one point).
In event of a two-way tie between the Blues and Wolf Pack, the Blues get the nod by virtue of their earlier 38-17 win.
The game is of interest to national team selectors with Canada taking part in the Americas Rugby Championship next month in Langford, B.C.
Because the Oct. 12-20 ARC dates fall outside the International Rugby Board's international window, Canada will field a domestic side and the CRC has proved to be a stepping stone to the ARC.
Bob Rogers, a 20-year-old prop for the Rock, is one of the CRC players getting a close look from selectors.
The Rock have been rebuilding this season and their game-day squad will feature six under-21 players and Alex Rogers, an under-19 player.
Chauncey O'Toole and Ciaran Hearn are among the internationals in the Rock starting 15.
The Blues lost national team players Mike Scholz and brother Mike and Dan Pletch to injury this season. But Doug Woolridge, Tom Dolezel, Jamie Mackenzie, Derek Daypuck, John Moonlight and Tyler Ardron are all familiar names on the Canadian rugby scene.
"It's been a big changeover from the team that won last year, and yet a lot of the young guys have really stepped up," Winokur said.
Ardron and Daypuck have been two key figures this season, according to the Blues manager.
The Blues will have travelled the breadth of the country in a week, having defeated the Pacific Tyee 32-17 on Vancouver Island last Saturday. The Rock defeated the Wolf Pack 29-26 in Calgary the same day.
The Blues have only won once in St. John's. That was last year.Suggest a correction