Not even the lure of a place in the 2009 NAB Cup Grand Final will tempt Essendon coach Matthew Knights to select his best available line-up for Friday night's semi against Collingwood at Etihad Stadium.

Knights confirmed on Tuesday that veteran defender Dustin Fletcher and midfielder Andrew Lovett, the club's best-performed player over the pre-season, would be rested for the clash despite the need to cover Mark McVeigh who will be sidelined for up to four weeks with an ankle injury sustained during last Friday night's win over the Brisbane Lions.

Bachar Houli and David Zaharakis, both of whom shone in the VFL at the weekend, and Brent Stanton, who's been sidelined for three weeks with a quad strain, are in contention for promotion.

"Stanton will come into the team if he gets through today's session definitely," said Knights. "But he has to clear some final hurdles with some kicking today with his quad."

"Michael Hurley and Tayte Pears are basically ready to play some game time this week; it's just whether they've done enough to come into a senior game."

"I guess with the substitute and the 26-man squad it gives you a lot more flexibility so it does bring them into the equation."

Knights said up to eight places in the line-up for Round 1 were up for grabs based on form over the remaining two weeks of the NAB Cup and NAB Challenge series.

Knights lent his support to the call from Collingwood counterpart Mick Malthouse to extend the use of substitutes, on trial for the NAB Cup, to the home and away season.

"I do like it," he said. "I would like to keep the interchange the same with four, and I would go with one substitute."

"But there would have to be real clarity on injury if that substitute was to be used."

"I wouldn't like a scenario where a player got taken off through injury and then a substitute came on and then that (injured) player played the next week."

"If it was done in the right manner and was regulated properly, I think the four interchange plus one substitute is a pretty good concept."