Tarrant is yet to play competitively for Fremantle this pre-season after missing the side's intra-club match and NAB Cup opener against Richmond.
But McPharlin said impressive form on the track should have Tarrant ready to take on North Melbourne at Manuka Oval this Saturday in his new defensive post.
"I'm very excited to see how he takes on the position in defence," McPharlin said from Fremantle Oval on Monday.
"When you're a forward and you go back you certainly know what can irritate a forward, so he's going to take all that experience. He's been pretty good so far – he's taken it on, he's a super athlete (and) he's got a great engine.
"We'll rotate on the bigger type forwards, but I think predominately I'll be deeper than he will be. We'll see how the season unfolds."
The defensive reshuffle has allowed Fremantle to trial Grover up forward.
Grover had a modest night in the three-point loss to Richmond, booting one goal and taking three marks.
But McPharlin said the 28-year-old's intimidating build should see him succeed in the new offensive role.
"You never know how a season is going to unfold but at this stage it looks like Grover will be trialled at full-forward," he said.
"It's a great position for him – he's a big, bulky, intimidating looking guy and he'll certainly intimidate a few young defenders this year."
McPharlin said he was preparing himself for a season played predominately in defence, however, his build-up was unlikely to include this weekend's clash with North Melbourne.
After a pre-season that he said had been 30-40 per cent more productive than previous years, the versatile defender said preparation for the round one clash with the Western Bulldogs was now the priority.
"I've done a fair bit of training and played a couple of games already," he said.
"It's about preparing for round one, so that decision [on travelling to Canberra] will be made later in the week for me.
McPharlin said his pre-season had been well managed under new strength and conditioning boss Jason Weber, who was formerly the physical performance coach of the Australian rugby union team.
McPharlin said captain Matthew Pavlich trained well on Monday morning and should make the trip to Canberra.
Luke McPharlin is rated a $314,800 forward in Toyota AFL Dream Team 2009.
Chris Tarrant is rated a $312,000 forward in Toyota AFL Dream Team 2009.
