PORT Adelaide assistant coach Matthew Primus says the club’s vacant second ruck spot is still up in the air four weeks out from the start of the home and away season.

The Power have spent all summer trying to unearth a replacement for retired big man Brendon Lade.

Former first-round draft pick Matthew Lobbe emerged as the frontrunner prior to Christmas, but lanky forward Justin Westhoff’s recent foray in the ruck has given the coaching staff something else to ponder.

In the past Port Adelaide has preferred to play two bona fide ruckmen but Primus said the emergence of Westhoff could see his side go into round one with just one recognised big man.

“Westy’s caught in between [positions] at the moment. Teams have had some great success over the last couple of years playing those kinds of [versatile] players in the ruck,” Primus said.

“We thought Westy was just going to pinch-hit in a couple of games, but he really impressed in our internal trial and he had a good quarter or so against the Crows.

“We haven’t played him in the ruck too much, so he’s learning all about it at the moment but he certainly gives us something that the big hulking ruckmen don’t.”

Lobbe, 21, also provides the Power with good flexibility.

The 200cm Victorian is one of the fittest players at the club and also has the capacity to play up forward.

Promising utility Jackson Trengove is another ruck option, but at 197cm tall is more likely to forge an AFL career in defence.

The Power’s young rucks will be given a chance to impress against West Coast's Nic Naitanui when the two sides do battle in the NAB Cup semi-final at Subiaco on Saturday.

Primus said playing against the athletic and agile Naitanui would be a great challenge for his emerging big men.

“We’re still not quite sure which way we’re going to go come round one. We’ve been happy with bits and pieces that they’ve done, but at the moment we’re not sold on who we’re going with behind Broges yet,” he said.

“They’ve all had good quarters and halves but we’re looking for a little bit more out of them. Time is running out for one of those guys to say they want the gig.”

Justin Westhoff is a $283,600 forward in this year's Toyota AFL Dream Team.

Matthew Lobbe is a $94,500 ruckman/forward.