NRL: History for and against Souths, Roosters

History is both for and against South Sydney and the Sydney Roosters heading into this week's NRL preliminary finals.

The grand final everyone wants to see - at least according to some North Queensland coaches and players - is odds-on favourite to be locked in this weekend, with the refreshed Rabbitohs and Roosters seemingly on a collision course for ANZ Stadium on October 6 since midway through the regular season.

Their opponents Manly, who play the Rabbitohs on Friday night, and Newcastle - who meet the minor premiers on Saturday - are battered, bruised and weary.

But history suggests the grand final everyone suggests is a given may not be so.

Only on four occasions since the NRL went to a top eight in 1999 have the two teams that enjoyed the week off both advanced to the decider, which happened last year when top two Melbourne and Canterbury met in the grand final.

Twice have the two rested teams both been knocked out in the preliminary finals, proving the Rabbitohs-Roosters blockbuster may not be the probable outcome many have come to think.

"It's 50-50 from here on in,'' Rabbitohs superstar Greg Inglis said.

"Individually it (the week off) helped me a lot, but in saying that, if you can get that roll on ... you can be very unpredictable.''

"It all could be undone in an 80-minute performance.

"You've got to really enjoy the process and enjoy training and really prepare for an 80-minute performance.''

While history may be against this year's two most dominant outfits both making it to the first Sunday in October, it does back one of them lifting the newly named Provan-Summons premiership trophy.

On nine of the 14 occasions the top eight has been used, the premier has been one of the two sides that enjoyed the week off.

The Roosters used the week off to get over a brutal qualifying final win over the Sea Eagles, and they may be boosted by the return of NSW Origin representative Boyd Cordner for the game against the Knights.

For the Rabbitohs, it allowed Inglis to give his ailing right knee a rest.

"It's the most talked about knee in Australia at the moment,'' Inglis said.

"The knee's fine, it is a blessing having the weekend off.''

The effect of the week off on teams in the NRL finals since top eight began in 1999:

Both teams qualified for grand final:
2012 - Storm (premiers), Bulldogs (runner-up)
2007 - Storm (*premiers), Sea Eagles (runner-up)
2003 - Panthers (premiers), Roosters (runner-up)
2001 - Knights (premiers), Eels (runner-up)

Neither side made grand final:
2005 - Eels and Dragons
1999 - Eels and Sharks

Premiers coming from one of teams which had week off:
2012 - Storm
2011 - Sea Eagles
2010 - Dragons
*2009 - Storm
2008 - Sea Eagles
*2007 - Storm
2003 - Panthers
2001 - Knights
2000 - Broncos

*premierships removed due to salary cap breach