The Norwich boss will take the opportunity of Saturday's fourth round encounter against West Brom at the Hawthorns to rest some of the squad who have worked such wonders in the Premier League this season.
It means Vaughan could play some part after making a goal-scoring return for the reserves in midweek after being sidelined for four months with a knee injury.
Defender Elliott Ward, another long-term injury victim, also returns to the squad, giving Lambert another boost as he seeks to capitalise on an impressive first half of the season.
Lambert said: "We'll mix it up a little bit. Some lads might need a break, they've been going week in and week out for us. I still think we have a side to go and win. I don't have any problem with changing the side. I have a group of lads who can adapt to it.
"I don't view any team I put out as being weaker. I've got great trust in the lads I play. We want to get through. We don't want a replay. We want to get the game finished tomorrow whether we win or lose."
The possible return of former Everton star Vaughan, in particular, gives Lambert another attacking weapon to support Grant Holt and fellow striker Steve Morison.
"A fully-fit James Vaughan will be a handful for anybody," Lambert said. "He has a good pedigree. He's an aggressive lad and probably his over-enthusiasm has caused him injuries. Get him fit and he'll be a big asset to us.
"In Wardy's case he was a huge part in getting the club where it is today. Hopefully the two of them are now ready to push.
"Wardy was excellent for me last year. He has missed most of this season and when he is fully fit I have four really good centre halves trying to get two places. That's what I need.
"They have battled through the frustration of being injured and now they are back in the group but I don't think they have ever felt out of it. No-one has isolated them. We have kept them involved with things.
"I couldn't throw them in (from the start). Not at the minute. They played part of the (reserve) game the other night but it would be unfair to throw them in to the intensity of the Premier League."
Lambert, however, hinted that Vaughan and Ward could make the trip to the Hawthorns where on-loan defender Kyle Naughton is unavailable at the request of parent club Tottenham.
Norwich go to the Midlands with the psychological advantage of having beaten West Brom 2-1 on their own ground earlier this month.
Norwich's new midfield signing from Leeds, Jonny Howson, has been meeting his new team-mates this week but is still around a month away from being fit for selection as he recovers from a knee injury.
Howson, who admitted Lambert was a big influence on his decision to join the Carrow Road, said: "When the chance came about I couldn't turn it down. I have seen the work he (Lambert) has done. When I spoke to him it encouraged me even more. It was all positive things.
"I like to get forward and chip in with a few goals and that is what I'll be looking to do. But mainly I'm a team player, leading from the front and setting an example."
Lambert is unlikely to bring in more transfer window signings and says he has received no offers for any of his players.
When asked if he would listen to bids for leading scorer Holt, he said: "Do you think I'd let him go?
"There's no point, if somebody comes in and says here's £100m for somebody then you just might look at it but there's no way on this earth you'd let anybody go.
"Same as any other team, they don't want to let their best players go."
