There was reason North Melbourne fought tooth and nail to keep Tristan Xerri last year.

A developing young ruckman seemingly stuck in a logjam behind the incumbent No.1 option Todd Goldstein at Arden Street, the 22-year-old emerged as one of the more surprising drawcard names for the Trade Period's deadline day when his proposed move to St Kilda suddenly stumbled.

North Melbourne had dug its heels in. The justification as to why might have played out over the ensuing three months.

Xerri has featured just 12 times in his first four years for the Kangaroos. Last season, he started the year behind both Goldstein and Tom Campbell in the pecking order for the ruck role. The club had since added the mid-season draft's first selection in Jacob Edwards and the talented Richmond youngster Callum Coleman-Jones to its selection mix.

Xerri's place in David Noble's plans therefore looked uncertain, but the Kangaroos still saw him as a key piece of their future. When the Saints failed to meet their steep asking price, which demanded a future second-round pick be involved in any potential deal for the contracted youngster, Xerri remained at the club he was drafted.

The thoughts of some North Melbourne fans might have immediately turned to an exciting one-two punch in the ruck featuring the former All-Australian and long-time servant Goldstein and the shiny new toy Coleman-Jones.

But the form of Xerri this summer has complicated things. Suddenly, a third name has entered the fray.

"I think the competition is between Callum and Tristan, that's the competition," Noble told AFL.com.au in an exclusive interview at Arden Street this week.

"We shouldn't discount Tristan. We went hard to keep him because we really value him. His pre-season has been outstanding. I reckon he's been in our top-three or four performers this pre-season.

"That internal competition is really growing and I think Todd knows that as well. We'd like to play two rucks, so it will be interesting over the next two or three weeks to see where that lands.

"We'll give all three of those guys an opportunity, both forward and in the ruck. At the end of the day, you pick the two best ones."

As for the race between Xerri and Coleman-Jones to support Goldstein, the victor may be determined by who can best impact forward of the ball. With young talents Nick Larkey and Charlie Comben set to start the year as the side's dual threat in attack, the Kangaroos are keen to involve a second ruckman alongside them.

"I've seen teams play three talls, with the third being the ruck," Noble said.

"Charlie has got some mobility. People probably haven't seen a lot of Charlie just yet … but he's got speed and you can add 'Larks' and another ruckman in there.

"Coleman-Jones and Goldstein are also mobile, so when they go down there they both bring different strengths to the table. 'Goldy' is really tall, he marks the ball and he reads the ball really well. 'CJ' has got that mobility to lead as a natural forward.

"There might be a point where we can play three talls."

Comben, in particular, has been another shining light on the track for North Melbourne this pre-season. Having made his debut in round 22 last year, the 20-year-old has continued to improve his physique and impressive aerobic capacity over the summer and the club is excited to watch his budding partnership with Larkey unfold.

"He jumps and launches at the ball really well," Noble said.

"That gives us the ability for us to go long and quick and deep to a forward line that's going to jump. 'Larks' plays that key forward role slightly different – but had a terrific year last year.

"Matt McGuinness is another one that's had a really good pre-season and we see him in that back-end, with his mobility and the fact he's a great left-foot kick. He's been able to take some strides forward."