PROLIFIC midfielder Chris Masten has won the Eagles' first time trial of the pre-season.

The Eagles ran a 2km time trial at WA Athletics Stadium on Monday morning after an eight-week layoff.

The club said the battle between Masten and fellow midfielder Andrew Gaff had become "somewhat of a tradition on day one of a pre-season".

However, young midfielder Damien Cavka might be one to watch in the future and make it a three-way battle after he broke Masten's 2km time trial club record last summer. Cavka did not take part in Monday's trial due to a foot injury.

Senior coach Adam Simpson said: "His (Masten) personal goal every year is probably the best (time).

"He always impresses in that.

"Gaffy always comes second, then there's a fair bit of distance between the next group.

"They've got exceptional endurance those two."

Chris Masten and Andrew Gaff set off in Monday's time trial. Picture: westcoasteagles.com.au

Meanwhile, defenders Eric Mackenzie and Mitch Brown will be challenge to adapt to the Eagles' new style of defending on their return from knee reconstructions, according to Simpson.

Neither player ran the 2km time trial on Monday morning but both participated in the subsequent training session with the main group. 

The Eagles were forced to restructure their defence last season after both Mackenzie and Brown suffered anterior cruciate ligament injuries in February and March respectively.

As a result, the West Coast successfully restructured their defence to a mobile zone where players guarded space more so than playing man-on-man. 

Simpson said the experienced key defenders would have to adapt.

"We've definitely evolved as a side," Simpson said.

"So how they adapt to what we've been doing is going to be a new challenge. I think they're pretty toey actually [on the] first day of pre-season.

"Both of them are coming off reconstructions so slowly, slowly will be the approach. We haven't changed that much but we're a little bit different to what we were 12 months ago."

Simpson anticipated both men would be ready to play in the NAB Challenge provided there were no hiccups during the pre-season.

The presence of Mackenzie and Brown could see Jeremy McGovern used in a different way in 2016.

McGovern made the All Australian 40-man squad last year following a stellar season in defence. He was swung forward late in the Eagles' Grand Final loss to Hawthorn and kicked two goals.

Simpson had previously stated that he would like to train McGovern as a forward during this pre-season and could even pinch-hit in the ruck.

"He sets his standards pretty high now," Simpson said. 

"I think he ran a personal best [in the time trial] pretty easily today. Hopefully we just see him mature as a regular AFL senior footballer. He's still pretty young."

New recruits Jack Redden and Jonathon Giles were on lighter duties on Monday along with Josh Kennedy, Brad Sheppard and Patrick McGinnity but all did enough running and skills work to suggest they are in good condition.

Youngster Alec Waterman had a very light session. He was delisted in October and then re-drafted as a rookie last Friday following a horror year during which suffered from glandular fever.