The Hawks have been under-sized in defence in the opening rounds, although Kyle Cheney and Josh Gibson have battled manfully on Brisbane and Essendon's power forwards.
It was hoped full-back Brian Lake would slot back into the senior team next round after serving his three-game suspension from the Grand Final.
However, Clarkson confirmed on Thursday the Norm Smith medallist has a calf concern which will delay his return to AFL ranks.
"He's just had a little bit of a calf complaint that's just upset his preparation, so he's another one that's going to need some match fitness," Clarkson said.
"As it was, it was going to be a challenge for us even if he didn't have a little bit of a hiccup to whether we'd bring him in round four with not much match conditioning.
"So this will at least allow us to give him some game time with Box Hill. Whether that's one week or two weeks…that will probably start next week I'd imagine, but it might not, it might be the week after.
"We'll just get some game time into him before we make a decision on when he returns to our senior side."
Fremantle has its own concerns heading into the clash at the MCG.
Star midfielders Nat Fyfe (suspended) and Michael Barlow (knee) will miss multiple games, while full-back Zac Dawson is also out of the Hawks game with a one-week ban for tripping.
Friday night's winner will move to a perfect 3-0 start to the season.
Clarkson admitted the Hawks needed to find another gear to match the Dockers, who have so far cruised to big wins over finals contenders Collingwood and Gold Coast.
"They're going well, they're playing some good footy and we weren't so good last week," Clarkson said.
"They're playing better footy than we are at the present time, in terms of the form line over the last two to three weeks.
"If that applies again tomorrow night they will probably be going home with four points on the plane on Saturday.
"But we think we can play a bit better than what we did the last week or two and if we can then we give ourselves a really good chance of winning."