The squad are four weeks into pre-season training but those burdened by last season's hectic international duties which began 12 months ago in the build-up to the World Cup, such as Rhys Priestland and George North, were assigned extended holidays.
Simon Easterby's side face a daunting RaboDirect PRO12 opener against Heineken Cup champions Leinster at Parc y Scarlets.
And although Harrington shrugged off suggestions they would be caught out fitness wise, he did warn the club's senior figures that their understudies are ready to make their mark this term.
"I'm not sure if it is a bigger challenge to get the international players fit for the start of the season," he said. "We have got a group coming in next week and then another the week after"
"The main thing for them was to have some down time after what they had been through, both mentally and physically.
"We have only got a small window to get them fit but they don't lose fitness overnight.
"They have got programmes and targets to achieve, so when they come back in they are ready to train rather than playing catch up.
"Every year it is getting a little bit better and they are coming back in better shape. We can then move on faster to the next stage.
"Last year was very demanding for the international players, especially in the Northern Hemisphere. We try to get our young players coming through ready to be able to adapt to it.
"It is extremely intense for them but I think we are good at managing them. Hopefully we will see those boys in a Scarlets shirt this year and pushing some of the other for places.
"Having more competition would be fantastic for us and would prove we have strength in depth."
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