One of the more unusual and undoubtedly painful reasons to scratch a horse has changed the complexion of betting on the $100,000 Canterbury Classic on Friday night.

Pre-post favourite Sessions was withdrawn from the Listed scamper on Thursday because of an issue with one of the assets which could make him a valuable stallion when his racing days are finished.

A Racing NSW stewards note on Sessions' withdrawal simply said: "Sessions will be scratched ... due to localised swelling in a testicle."

Sessions was also an acceptor for Saturday's Warwick Farm meeting, and although the exciting colt will also miss that engagement, he is unlikely to be sidelined for too long.

In a reshaped market, Canberra sprinter Unanimously is the new Classic favourite at $3.50 from Didntcostalot ($5) and Uate ($5.50).

While Sessions added much interest to the race as a serious up-and-comer, the three-year-old's absence will have no bearing on the tempo with natural speedsters Zaratone, Uate and Didntcostalot expected to provide a breakneck pace.

It will be a tempo which could suit a run-on horse and trainer Jarrod Austin says his sprinter Territory fits that profile.

"There will be plenty of speed on and I'm hoping he can hold his position on the rail behind them and not get shuffled back," Austin said.

"If he can he'll finish the race off just as well as anything. We just don't want to be giving them too much start coming to the corner."

Territory ran second to Sessions when the Darley colt posted track record figures for 1000m at Warwick Farm and Austin has stuck with hard-working jockey Patrick Murphy for the $10 chance at Canterbury.

Once he recovered from the shock over the race time Sessions ran to beat Territory, Austin said he was satisfied the horse who started to make a name for himself as a three-year-old was now ready to catch up on lost time as a five-year-old.

"He seems to be back on track now," Austin said.

Hopes are also high about topweight Whitefriars regaining a semblance of the form which had him rated as one of Australia's emerging sprinters in 2011.

"He's obviously a quality horse and he's got the weight to carry because he's got better performances than the rest, albeit not of late," jockey Glyn Schofield said.