Martin Truex Jr. might be without his regular crew chief for a second straight race.

Chad Johnston stayed home from last week’s race at Pocono Raceway to be with his wife, Stacey, who is expecting their first child. He was replaced by Michael Waltrip Racing executive vice president of competition Scott Miller.

As of Tuesday, MWR said Johnston’s wife still had not given birth, and Miller was prepared to serve as crew chief again this weekend at Michigan International Speedway if necessary.

“The whole NAPA team is awesome,” Johnston said in quotes provided Tuesday by MWR. “I couldn't ask for a better group of guys whether it's the road crew, engineering staff or the shop folks at Michael Waltrip Racing — they all know what they need to do. Regardless if I am at the track or not, no one ever gives less than 110 percent. That includes me too. I'm in constant contact with everyone.”

Indeed, Johnston stayed in contact last week via phone and computer.

“The only real challenge I had was when I had a limited wireless connection,” he said. “If I stay home this weekend, it will be OK. I discovered NASCAR's RaceView. It is an easy way to follow the race.”

Truex, a Stafford Township, N.J., native, has revived his career since Johnston took over for Pat Tryson midway through last season. But Johnston said the rest of the crew has been important also.

“Last week at Pocono, my normal engineering staff was at the track who has worked with Martin for more than two seasons,” said Johnston, who served as the head engineer before being promoted to crew chief. “They understand him as well as I do so there were no translation problems.”

Miller has solid credentials, too. Earlier in his career, he served as crew chief for Jeff Burton and Dave Blaney, and he was a crew member for Kevin Harvick and Robby Gordon.

“Scott Miller is one of the best strategists out there,” Johnston said. “I've gone to him a few times during races to bounce things off of him, so if Scott is on the pit box again, the NAPA team is in good hands.”