The 29-year-old - who has won two Grand Finals with the club in 2006 and 2014 - has issued a rallying cry to his teammates ahead of Friday's clash, and the England international believes his team can replicate their performance levels from last year.
"We are in the semi-final now so there are no excuses – we have to start well, and not be trying to build into it after 10-20 minutes," Roby told the St Helens Star. "We are 80 minutes away from the Grand Final and they don't come much bigger than this now.
"It was a negative time after the [Challenge Cup] semi and morale was a little bit low, but you can never lose sight of how good we are and let's not forget we are still the defending champions.
"We have done the hard stuff on the pitch, turned it around and got ourselves out of that rut. We have no excuses this year, we are more than capable and have done it before."
Roby has made 333 appearances for his hometown club, scoring 85 tries.