FOR YEARS Brad Johnson has been the key target of an undersized Bulldogs forward line, but that may be left in the past after the club's investment in tall timber at November's NAB AFL Draft.

The Dogs' three selections – Ayce Cordy, Jordan Roughead and Liam Jones – all stand at least 195cm and Johnson says height will be a signature of future teams.

"The guys are first-year players and it just depends on how fast they develop," he said. "Some guys can come in and step right into it. Some guys take maybe one or two years to get used to playing senior footy.

"I think over the next couple of years definitely you will see a change. We’ve got two or three really tall young forwards coming through with a bit of luck."

While Johnson is excited by the new litter, he stopped short of putting immediate expectations on any of them.

"You can’t single anyone out at this stage," he said. "They’re all finding their feet and working really hard.

"Hopefully in a month's time I will be able to answer who is starting to step up with their on-field stuff."

The Bulldogs made it to a preliminary final in 2008, however, Johnson and his teammates are aware of the gap between their side and grand finalists Hawthorn and Geelong.

"The challenge is there to maintain and also improve our performance last year," he said. "We started the season very well and were able to maintain it for a fair while but we dropped away towards the end part of the season.

"We need to find probably 15 to 20 per cent on last year's performance to even compete with Geelong and Hawthorn. There's going to be other sides who step up so we need to make sure we're on our mettle and on our game so we can continue to step right up there and be a force in the comp."

The 32-year-old said he was once again expecting big things from Brownlow Medallist Adam Cooney.

Johnson, who began his career with previous winners Scott Wynd and Tony Liberatore, said the entire squad would benefit from Cooney claiming football's highest individual honour.

"That’s fantastic for Adam and our footy club to have another Brownlow Medallist running around with us," Johnson said.

"He’s extraordinarily focused, he’s kept his body right and he’s keen to start the games so he can get back out there and let his footy do the talking."