MARTINSVILLE, Va. — A crew chief can’t make a slew of changes to help a driver get around Martinsville Speedway once the race starts Sunday.

A change here or there could help slightly. But the driver has to find the best rhythm to take care of tires and brakes.

A crew chief, though, could become vital if a driver suffers damage, especially in this age of the five-minute clock for repairs. Directing the crew can be as dicey as a driver trying to make it through the tight Martinsville corners on the 0.526-mile paper-clip-shaped track.

Having an experienced crew chief could be key, so it’s not a surprise that Stewart-Haas Racing wanted an experienced crew chief in Daniel Knost to take over for the suspended Rodney Childers on Kevin Harvick‘s car for the STP 500, an expected grueling 500-lap affair Sunday afternoon.

Knost won at Martinsville as the crew chief for Kurt Busch in 2014. He spent two years as a Cup crew chief, working with Danica Patrick and Busch before moving into a director of vehicle dynamics role.

Childers was suspended for one race last year thanks to the NASCAR lug nut rule at the time. He’s out for one race this go-round for an unapproved track bar slider assembly at Phoenix.

“It’s definitely not going to be the same, but you have to manage these situations the best you can,” Harvick said. “We’ve been here before and had to manage these types of situations, so we have a little experience looking back on how we did this last time and hopefully we can do it better.”

Harvick won’t be the only driver with a new voice in his ear. Daniel Suarez will have Scott Graves calling the shots as the replacement for Dave Rogers, who abruptly left his role this past week.

Suarez and Graves have worked together in the Xfinity Series. But Graves hasn’t worked a Martinsville Cup race since 2013 when he was a crew chief for Ricky Stenhouse Jr.

“It was a pretty easy answer to have Scott come up and do it for him since he’d had so much success with him in the Xfinity Series,” said Suarez teammate Denny Hamlin. “It would take a crew chief a long time just to kind of understand Daniel [with his accent] inside the car, so I think someone having that experience with him was a must.”

What to watch for Sunday at Martinsville:

Good cars not up front

Chase Elliott will start second, but he might not remain there for long. With the lineup for the STP 500 set by points after rain and lightning Friday, Elliott likely will get stuck on the outside lane.

He also probably doesn’t feel strong enough to start second. He was 23rd in the opening practice session Friday.

Some of the fastest drivers won’t start near the front. Denny Hamlin, who posted the best speed in Friday practice, will start 12th. Kyle Busch, second in practice, starts 10th.

Jimmie Johnson, with nine career Cup wins at Martinsville, will start 17th.

“If you have your car driving well and you know what you’re doing here, I don’t really think it matters where you start,” Elliott said. “Jimmie Johnson is going to prove to us all how much it matters where you start here on Sundays.

“So watch him move forward and you’ll see a guy who knows what he’s doing, who knows how to pass and has his car driving like he needs to be really good.”

The good or the bad?

Speaking of good cars possibly sprinkled through the field, it is a reminder that of the five organizations that have won this year, Hendrick Motorsports or Joe Gibbs Racing is not among them.

The winners have come from Stewart-Haas Racing, Team Penske, Furniture Row Racing, Richard Childress Racing and Chip Ganassi Racing.

Of current drivers who have Martinsville wins, JGR and Hendrick have 16 of the 20 victories — Johnson with nine, Hamlin with five and Kyle Busch and Dale Earnhardt Jr. with one apiece. The only other active drivers with wins at Martinsville are Kurt Busch (two), Harvick (one) and Ryan Newman (one).

The biggest surprise among the winless might be Johnson, coming off his seventh Cup championship season.

“It’s easy for me to get sucked into trying harder and making mistakes and when you are not going forward [than] to say, ‘All right, let’s back off 10 percent and the car will go faster’ — [that] is the last thing you would ever imagine working or happening,” Johnson said. “So it’s tough [and] it’s easy to get sucked into an environment to make mistakes as a team and driver.

“As odd as it may sound, I think we are guilty, we are really guilty of that right now and we’ve got to dial that in.”

At least Johnson has only a five-race winless streak. The other Hendrick drivers are Earnhardt (24), Elliott (46) and Kasey Kahne (88). The JGR veterans: Hamlin (15), Kyle Busch (21) and Matt Kenseth (22).

Unproven tires

Cup teams will have nine sets of tires for the race. They will have a sticker set on the car to start because qualifying was canceled. They will have eight sets of sticker (new) tires in the pits.

That’s two fewer sets of tires than a year ago, and if drivers get impatient, causing a flurry of cautions (especially near the end), teams might rather have track position than burn a set of tires.

The right-side tire also is new for Martinsville this year. The new compound — the outside layer — is designed to wear into the track better. The construction of the tire, how it’s actually made, is the same as in the past to handle the punishment of braking and heavy loads.

“I thought it laid rubber way faster than it has in the past,” said Kyle Larson, who will start from the pole, about practice. “At least you could see it and maybe because I was tight I just felt it more, but to me it seemed like it laid rubber a lot easier.

“That will definitely impact the race and probably make it a better race. It will probably allow the groove to move around some because I think people’s cars will not handle the way they want them to and they will kind of chase the car up the track a little bit to stay out of that rubber.”