The representative forward has signed to join Souths on a four-year deal from 2021 but the Rabbitohs are still trying to secure a deal to get him for 2020 to fill the gaping hole left by Sam Burgess' retirement.

Preparing for his first season in charge of last year's wooden spooners, Holbrook on Tuesday declared Arrow a vital part of his team for the upcoming season.

"We're not just going to let him go ... my plan and the club's plan is that Jai's playing here in 2020," Holbrook said.

"He's a great player, he's a committed type of player and we know he's an important part of our team.

"He had a big decision to make on his future, he's made that now, but he's committed to playing 2020 and that's how we'll be seeing it out," Holbrook added.

"He's a really good guy at the end of the day and obviously a very good player. I see him being a big part of our season this year."

Arrow joined the Titans in 2018 from Queensland rivals Brisbane and quickly established himself as one of the best players at the struggling club.

He made his Queensland State of Origin debut the same year and was desperately missed by both the Titans and Maroons after suffering a mid-season ankle injury.

Holbrook has also thrown his support behind halfback Ash Taylor.

The playmaker endured a horror 2019 which included a break from the game due to personal reasons but the new Titans coach has been impressed by the 24-year-old's early pre-season efforts.

"I've been really happy with Ash straightaway. I think he's really applied himself well to everything he's done with his training," Holbrook said.

"I've made it clear I'm here to help him and I want him to play as good as he can, just as much as everyone else does.

"It's my job to help him achieve that but he's got to help himself and he's doing that and doing it really well."

Australian Associated Press