The names of those set to chase Stewart in the final round are much more familiar.
Stewart, who only made this week's tournament by surviving a 10-man playoff in a Monday qualifier, shot a 4-under 68 and will take a surprising four-shot lead into Sunday's final round.
'Who's to say he's not supposed to be up there?' said Scott Hoch, who will be in the final group with Stewart on Sunday, four shots back.
'We have a lot of good players who have to qualify, and it's not surprising to me at all that we have a guy who is qualifying and playing this well.'
Stewart wasn't rattled playing in the last group, making 12 pars and taking advantage of his birdie opportunities. His only hiccup came on the par-3 17th, when a poor tee shot led to Stewart's first bogey of the tournament.
Stewart started with a long birdie putt on the par-5 first hole, then added birdies at Nos. 8, 10 and 14. He rebounded from his only bogey, with a delicate pitch from the rough to 2 feet on No. 18 and his fifth birdie.
The native of Abbotsford, British Columbia, is playing in his first tournament since the 2006 Senior British Open and trying to become the first qualifier to win a Champions Tour event since Pete Oakley at the 2004 Senior British Open.
Ten players in tour history have qualified that week and then won an event.
While Stewart is a relatively unknown, the group set to try and chase him down on Sunday is full of marquee players with experience closing out victories. Seventeen players are within six shots of the lead.
Hoch made six birdies and one bogey en route to a 5-under 67, on a day when his ball striking was inconsistent and he let out an 'ouch' after miss-hitting his tee-shot on the 18th. But Hoch took advantage of a handful of strong approach shots, making four birdie putts inside 10-feet.
After a warm, sun-filled first round on Friday, Hoch knew some weather was on its way Saturday, when both he and his wife had arthritic aches in their hands. The cool, cloudy Saturday afternoon didn't squeeze out much rain until after Hoch finished.
'I played much better yesterday and shot 1 under. Today, nothing great, but just didn't get myself in trouble,' Hoch said.
Denis Watson, Bruce Vaughn and Gil Morgan all joined Hoch at 6 under. Vaughn also played in the Monday qualifier and didn't gain an automatic spot in the field, but was the first alternate and got in the field when Jim Dent withdrew.
Craig Stadler shot the lowest round of the day, firing a 7-under 65 to get to 5 under for the tournament. After making just two birdies in his first round, Stadler made seven on Saturday and eagled the 590-yard, par-5 15th.
The group at 5 under also includes Mark O'Meara, who shot 68, making just one bogey a day after bogeying three of his last four holes.