He holds the course record at Carnoustie with a 63 at the Dunhill Championship previous year and also shot 63 on the final day of the US Open last month to finish second behind Brooks Koepka. With 28 players under par after two rounds, and 39 within six shots of the lead shared by Americans Zach Johnson and Kevin Kisner at six under, it feels like multitudes contend.
The 42-year-old began the day on level-par for the tournament but took full advantage of ideal scoring conditions to join six other players on six-under. A birdie at 10 was handed back at 12 before further shots picked up at 13 and 14 saw him get to -5.
Then there is Tiger Woods, who shot 66 Saturday, at 5-under and tied for sixth with a list of players including Rory McIlroy, Zach Johnson, Tommy Fleetwood, Matt Kuchar, Webb Simpson and Alexander Noren.
Before heading to the course on Saturday, Spieth went into Carnoustie for what he called "a very British haircut", just as Tiger Woods was rolling back the years with his third-round 66 in front of huge galleries.
While Spieth went for a very traditional look with his makeover, his fellow American Rickie Fowler, with whom he is sharing a house this week, opted for something a whole lot more notable for Sunday's final round. "I just need to regroup and get ready for tomorrow".
No one took advantage of the calm conditions like Rose, who played bogey-free from the third group out and shot 64.
"I haven't played it in that much wind". Woods then bogeyed the par-3 16th, getting a bad break off the tee and failing to get up-and-down from off the green.
It's time for moving day across the pond. The No. 2 player in the world, Justin Thomas, also was headed toward a weekend off. Thomas was 2 under for the tournament when it took him two shots to get out of a pot bunker in the sixth fairway and three putts from long range on the green, leading to double bogey. A rugged start, a strong recovery, a few putts for birdie, a few he missed for par, and it added to an even-par 71.
"Hopefully I can get some nice weather tomorrow".
His move started with a sudden decision. Spieth, who spent Saturday morning watching the Open on television, asked caddie Michael Greller on the practice range, "Do we like driver?"
"I'm committed to making sure that even if I don't play my best golf and don't shoot the scores I want, I'm going to go down swinging and giving it my best". The wind is supposed to pick up a little bit.
This is the 16th time he has been in at least a share of the lead in the majors in the five years he has been playing them on a regular basis. This is the first time since 2014 that Spieth has arrived at The Open Championship without a victory, but he seems to have made progress with his putting.