Nat Fyfe feels he’s no certainty to play Sunday’s RAC Derby at Optus Stadium after making his return from a hamstring injury against St Kilda in round six.

Fyfe’s main concern post-game was a cork in his left leg, but on Tuesday he also experienced ‘awareness’ in his right hamstring.

The midfielder remains confident he can play but said Fremantle may decide to take a conservative approach.

“The hamstring probably hasn’t pulled up as well as I would have liked and that’s not uncommon with hamstrings, just to get a little general awareness,” Fyfe said.

“We’ll monitor that throughout the week. We’re a bit compromised with how much training we can do at the moment but I will do everything I can to be available for selection.

“The cork will just take some time as well.

“(I’m) pretty confident (I’ll play) but there’s always a chance with these things, they could go either way.

“We’ve just got to wait and see how it responds and pulls up. As I’ve previously done a hamstring injury on this side we’re a little more cautious than we’d otherwise be.”

Fyfe spent most of the second half of Freo’s win against St Kilda in the forward line and the midfielder said he was open to occasionally playing up front.

“I think (playing forward) would be something JL (Justin Longmuir) and I will work to get the balance right with,” Fyfe said.

"You shouldn’t be surprised to see me play a full game forward or a full game in the midfield.

“Maybe just an attacking option going down the line. Rory Lobb, Matt Taberner and Jesse Hogan have been giving us some great structure but with a couple of those guys shifting positions, I think I add another element down there.”