Now with the competitive action about to get underway, Priestland finds himself back in the firing line as the Scarlets take on last year's champions. It is a daunting start for Simon Easterby's side but after such a lengthy injury period, Priestland must be raring to go.
The Wales man suffered his Achilles injury against Exeter Chiefs late last year, missing Wales' Six Nations triumph as a result. He returned at the end of the season but the injury flared up in the build-up to their play-off clash with Ulster, keeping him out until the start of this campaign.
His return to fitness is a boost to head coach Easterby who is hoping is side can string together a couple of early wins.
"We need a strong start, a good result and a performance like last year's opening game would give us real momentum going into the next series of fixtures," he said.
"We know Leinster are always going to be competitive. They are very effective and efficient with ball in hand and will be a challenge to us.
"All teams are looking for form in their opening game and want to hit the ground running, regardless of how long the season is."
For the meeting with Leinster at Parc y Scarlets, Priestland is partnered with Steve Shingler and Scott Williams in midfield as Gareth Maule is expected to be out for four weeks with a knee problem.
Otherwise, Easterby keeps much the same side that started at Kingsholm with Rob McCusker leading the side. Wales centre Jonathan Davies and Scotland flanker John Barclay are the only notable absentees.
The Scarlets will be looking for another strong start to their PRO12 campaign and with it a repeat of last season's opening fixture. This time last year they secured a 45-20 home win over Leinster, Liam Williams scoring one of a number of tries.
"We're in a very positive place as a group. Fitness wise we've been able to pick from a near full strength squad so that's a bonus and the boys are eager to get going," added Easterby.
"It's a great fixture for us to have first up and everyone's in a positive and upbeat mood so hopefully it will be a lively night at Parc y Scarlets. We are really looking forward to getting our season started now after a lot of hard work on our pre-season preparations."
Going into his second season in charge of the Scarlets, Easterby is focusing on having a strong team around him.
He said: "For me, it's all about the environment you create, having the right people around you and maintaining a positive atmosphere.
"On the whole, the players here are happy with the way we want to play and we're certainly going in the right direction.
"We showed last weekend if we keep our discipline and keep hold of the ball we can be really effective and I was pleased with how our set-piece play went - that was a real positive for us."