McCumbee, who races full time in the Craftman Truck Series, made his Cup debut last year in the No. 45 while Petty fullfilled his television commitment for TNT. McCumbee made two starts during Petty's six-race absense with a 25th-place finish in his first start, in June at Pocono.
McCumbee
"Everyone at Petty Enterprises believes in Chad and his abilities," Petty said. "At Pocono, he did a great job filling in for me when I went into the booth. Texas gives us a chance to get another good look at Chad without throwing him to the wolves. He should be relaxed because he knows he can get the job done there."
McCumbee has made three Truck Series starts at Texas, with one top-10 and two 13th-place finishes. McCumbee qualifed second his last time out at Texas, but a late-race crash took him out of contention.
"Texas is a good track for him," Petty added. "He had a strong run going in the Truck race there last year."
McCumbee, 23, will test in the No. 45 on Wednesday at Kentucky Speedway. Texas will mark McCumbee's first attempt in the new car.
"I feel comfortable around the No. 45 team," McCumbee said. "[Crew chief] Billy Wilburn and I work well together.
"We're planning on going to Kentucky Speedway on Wednesday for a test, just to help me get used to the new car. The two races last year were in the old car, so there will be a little bit of an adjustment period there. I don't have a lot of experience in the old car either, so maybe that will be a positive."
The No. 45 sits 40th in owner points, meaning McCumbee will need a good qualifying run to make the race. Petty failed to make the field last week at Martinsville, the first time since 2004 the No. 45 car wasn't in the starting lineup.
"I'm anxious to do my part to help this team," McCumbee said. "We had a great race last year at Pocono. I'm hoping for more of the same this weekend.
"Kyle is going to be there, giving me advice and pointers. That means a lot to me. I've learned a lot from him already."