All five drivers were born outside the continental United States.
All five have competed in NASCAR Sprint Cup Series races at Sonoma Raceway.
And none of the five will be competing in Sunday's Toyota/Save Mart 350 at the picturesque Northern California track.
The aforementioned five drivers were once part of a group known as "road-course ringers," who were frequently found at Sonoma and Watkins Glen International, the two road courses on the Sprint Cup schedule.
The road-course ringers were drivers from non-NASCAR disciplines brought to Cup road-course races for their road-racing expertise. Most had backgrounds in sports-car racing and occasionally open-wheel racing. Ekstrom, for example, was a two-time DTM touring-car series champion in Europe.
A decade ago, the field at Sonoma had nine road-course ringers: Scott Pruett (3rd), Boris Said (6th), Klaus Graf (17th), Jim Inglebright (19th), Larry Gunselman (37th), Austin Cameron (38th), P.J. Jones (39th), Brandon Ash (41st) and Tom Hubert (43rd).
This Sunday at Sonoma, Said and Tomy Drissi will be the lone road-course ringers.
So what happened?
Once upon a time -- and not that long ago -- it was thought that one of the keys to victory at Sonoma could be to employ a road-course specialist behind the wheel.
But not anymore.
The truth is that while a lot of the road-course specialists could run fast lap times, rarely were they around at the end of the race, at least not when it came to challenging for victories.
The other part about it is that the Sprint Cup regulars as a group have become much more savvy about road racing. And that means fewer opportunities for the ringers.
"The garage area sometimes grumbles when we go to road courses," said Kurt Busch. "I think that mentality has changed. Everybody has to accept that road courses are part of the NASCAR culture."
And with NASCAR's new format for the Chase for the Sprint Cup, Sunday might be the best chance of victory for some drivers who are winless so far this year, and so they put more effort into this race than other events.
"When it comes to winning, this is one race that has been circled on the schedule," said Truex, the defending race winner. "However, there are so many excellent road course drivers right now and I am sure this race has also been circled on their calendars as well. That's why Sonoma is a great race."
"I think it does throw a dynamic into the Chase format where you're going to have maybe one or two guys that you typically wouldn't see in the Chase that are just really good at road courses, but not necessarily everywhere else," said Brian Vickers. "We'll see. Only time will tell."