Clarke hasn't played in the first-team since limping out of the 3-1 win over Stoke City at Deepdale in August.
He returned to feature in a bounce game at the training ground against Accrington Stanley last week but suffered a slight reaction.
But there was better news on left-back Andrew Hughes who has only played once since August due to hamstring and hip flexor injuries.
North End manager Alex Neil speaking at Springfields on Thursday morning said: "Clarkey in the game just aggravated his knee, it's not actually the same injury but it is in the same area.
"That will probably put him behind a little bit.
"Hughesy has been fine so we hope he will continue to be for the rest of the week."
Alan Browne and Sean Maguire were both back at the training ground after being on international duty with the Republic of Ireland.
Browne featured in both of Ireland's Euro 2020 qualifiers, coming on as a substitute against Georgia last week and starting Tuesday's 2-0 defeat to Switzerland. Maguire was an unused substitute in both matches.
Neil said: "Alan did more than what Sean did so we have to be a little bit careful with that, otherwise they are fine.
"It was a productive week for us in terms of getting a lot of bodies rested, we had the bounce game in there as well, we are hopeful we can pick up where we left off."