THE SYDNEY Swans could have a very different look from the team that claimed last year's flag when they kick off their premiership defence in just over two weeks' time.

Alex Johnson has already been ruled out for an extended period due to his knee injury, and at least three other members of the side that knocked off Hawthorn in the Grand Final are in a race against time.

Fellow backmen Nick Smith (knee) and Marty Mattner (hip), plus forward Mitch Morton, haven't played a minute of the pre-season yet, with round one against Greater Western Sydney on March 30 looming large on the horizon.

Shane Mumford played just over a quarter in his first game last Saturday and needs to build his match fitness in this Saturday's final practice game against Port Adelaide, while Adam Goodes has also been limited during pre-season.

"We'll see what happens for round one," coach John Longmire said.

"We've still got a few weeks to go and we'll see what happens this week.

"What we're conscious of is not playing too many players (in round one) that haven't had the right amount of preparation.

"Nick Smith and Marty Mattner are the guys that need to get some game time over the next two weeks.

"Mumford played about a quarter on the weekend and did OK, but we need another hit out from him this weekend."

There are question marks over Morton, who broke into the side late last year and kicked two goals in the Grand Final.

Laid low by an ankle injury and then a back problem, Longmire said Morton could return to action this week, but seems a long shot to play in round one.

"We think he's good enough to play in our senior team, obviously, but whether he, combined with Mattner, Smith, Mumford, Goodes … can you have them all in the one team?" he asked.

"That will be the challenge for Mitch and maybe one or two others.

"We need to get some game time into an enormous amount of players this week."

Longmire does have some options, with Tony Armstrong pressing for a spot in the backline, while Tommy Walsh is being considered for a defensive role and rookie Dane Rampe has shown promise.

With Gary Rohan being put on the long-term injury list, the coaching staff will decide next week whether someone needs to be promoted, with Rampe in front of Jake Lloyd.

The Swans are confident whoever gets a chance will play their role, using Nick Malceski as an example after he battled back from being dropped midway through 2012 to feature strongly in the push to the flag.

"We could (have a different look in round one), but that's the way it happens," Longmire said.

"Malceski was playing reserves half way through the year, but got an opportunity because Marty Mattner went out at the last minute and stayed in for the rest of the season.

"So it's not unusual. It's what happens. Players come in and out of the team through form and injury and others grab their chance."

James Dampney is a reporter for AFL.com.au. Follow him on Twitter: @AFL_JD