Josh Jackson admits there were some "challenges" that came with his debut year as an NRL club captain but is excited about what a refreshed Bulldogs roster can achieve.

Dogs players returned to training last week with new faces Corey Harawira-Naera, Sauaso Sue, Nick Meaney, Jack Cogger, Chris Smith and Christian Crichton on deck.

"There's a lot of competition this pre-season, we've got a lot of spots up for grabs and all those players are going to be big players in the future," he told NRL.com.

"Jesse Sue is an experienced player and we're lucky to have him on board. He's really skilful with the footy, he's got great footwork and he's a really aggressive player in defence which is really the type of player we're looking for.

"Plus the experience he brings, I'm really looking forward to playing with Jesse and seeing what he has to offer.

"Some younger guys in Nick Meaney and Jack Cogger from Newcastle who have played a little bit of first grade will be itching to try and nail down a spot over the pre-season.

"Corey has been unlucky, he was picked for New Zealand after the season and had a few issues with injury but I'm sure he'll play a lot of Tests in the future."

In 2018 the Bulldogs benefited from the emergence or development of players already within their squad - Lachlan Lewis and Rhyse Martin were eye-catching at times.

The progress of forwards like Renouf To'omaga, Ofahiki Ogden and Francis Tualau will be even more important if Test prop David Klemmer is released to take up a lucrative offer from Newcastle.

While Jackson was hopeful Klemmer would remain at Belmore, he was also encouraged by the depth among the forwards.

"Those guys got a bit of a taste last year and no doubt they'll be playing a lot more first grade this year," he added.

"They had a fantastic season in the ISP [Intrust Super Premiership], winning both competitions [the ISP and State Championship against Intrust Super Cup winners Redcliffe]. They're not back at training yet but I'm really excited to get those guys back – there's a lot of competition for spots [in the pack]."

Jackson's leadership impressed many as he and Pay helped the squad recover from a hugely disappointing first half of the season to show plenty of spirit to win four of their final six games.

"[The captaincy] is still growing and something that was really new to me at the start of the season but I really enjoyed it," Jackson said.

"It was challenging, there were a lot of obstacles and things that went on during the season we had to get through but I can't take credit for [the turnaround at the end], that was the whole team and Deano especially as a coach, it was a hard first year for him as well but the group we have and the relationships everyone has with each other.

"We've only been training together this last week and those guys fit in really well. Everyone's getting along well and that's a big part of being a successful team.

"We went through a fair bit [in 2018], a lot of media speculation and a lot of other things went on during the year so I'm really excited to put that behind us.

"It's a very new team, very young squad we've got together this year so we'll spend the summer getting to know each other, getting to know each other's games.

"I'm really excited about the next couple of years. I think we can achieve a lot in the next few years together."