FORT WORTH, Texas (AP) — Jimmie Johnson will have more on his mind in September than the start of the NASCAR Chase for the Sprint Cup championship.

Johnson announced this week that he and wife, Chandra, are expecting their second child in September.

"Our doctor has told me that a father has never missed a birth," Johnson said Friday. "That gives me a lot of confidence that I will be able to do my weekend job and then be around during the week to meet number two."

Johnson was prepared to miss a race three years ago if his wife went into labor, but their daughter was born on a Wednesday in July 2010. At that time, Johnson had Aric Almirola on standby if he needed to leave a race.

Johnson has already won twice this year, winning at Martinsville last week and taking over the points lead. There is no backup driver in place yet for September, but the five-time Cup champion said he will be prepared again for the birth of his second child.

"We still have some time. We are not sure who will be available come that time," Johnson said. "I was joking with Aric Almirola last weekend that if he wanted to be my back-up driver again, he clearly has a full-time gig and can't do it. We will just have to see, but we will definitely have a plan like always. We will be buttoned up. "