PORT Adelaide coach Mark Williams says he expects injured midfielder David Rodan to be back playing before the mid-season break.

Rodan joined his teammates at training on Tuesday for the first time since rupturing the anterior cruciate ligament in his left knee in December, but he is ineligible to play until at least round two as he has been placed on the club's long-term injury list.

But Williams said Rodan’s impressive training form was becoming hard to ignore.

“My heart was racing a little as David was going through a couple of those chicanes (cones and other obstacles),” Williams said after training on Thursday.

“He was starting to move sideways and do some of the great things everyone knows he can do in footy, so he doesn’t look too far away.”

Thursday marked exactly 11 weeks since Rodan had revolutionary LARS (Ligament Augmentation and Reconstructive System) to repair his torn ACL.

Sydney Swans’ defender Nick Malceski returned to the field in just 12 weeks after having the same procedure.

Williams admitted Rodan was close to being physically ready to play, but said he would also need to be mentally prepared before he could make his AFL comeback.

“You’d imagine David needs four or five weeks of really solid training where he’s getting tackled, smashing people and getting up with some confidence. I think his head’s more important now than his body,” Williams said.

“I would really expect that by the mid-season break he’d be playing. He definitely won’t be playing round one and it’ll be really up to when we think he’s 100 per cent ready.”

Rodan could battle to get his spot back with the fierce competition for spots developing at Alberton.

Defender Jackson Trengove, onballer Tom Logan and half-back Marlon Motlop have all been left out of the 26-man-team to take on the Western Bulldogs in the NAB Cup semi-final on Friday night.

They will be replaced by experienced quartet Warren Tredrea, Dean Brogan, Robbie Gray and Travis Boak.

Daniel Motlop is the only first-choice player missing from the line-up and Williams said it would be tough to trim the current squad back to 22 players come round one.

“I had to go and talk to a couple of players about not being in the side and they’ve actually been going okay [in the first two games],” he said.

Ruckman Matthew Lobbe has also been omitted from the team, so the coaches can have a good look at rookie-listed tall Cameron Cloke.

Cloke, Brogan and Justin Westhoff will do battle with Bulldogs Will Minson and Jordan Roughead at Etihad Stadium on Friday night.

Williams said he expected a tough challenge against the “most prepared” side in the competition.

“We’ve had a short week. We’ve come back from [playing in] 40 degree-heat and we have to fly two weeks-in-a-row… you can give us as many excuses as you like, but we’re not using any of them," he said.

"We’re going out there and really looking forward to playing at Etihad Stadium and getting a great result.”

David Rodan is a $305,500 midfielder in this year’s Toyota AFL Dream Team competition.