Hornish, who competed in three Verizon IndyCar Series races on the challenging California road course, will provide commentary along with another Indy car champion, Paul Tracy.
Brian Till is the lead announcer for the live race (4 p.m. ET Aug. 24) and qualifying (7:30 p.m. ET Aug. 23) telecasts.
It will be the initial IndyCar broadcast for Hornish, who has contributed to NBCSN's "NASCAR America" this year and previously contributed to NASCAR Nationwide Series practice and qualifying telecasts on FOX Sports 1 and "SpeedCenter" on SPEED (the predecessor to FOX Sports 1).
"(NBCSN does) a really good job of keeping it fresh with Townsend (Bell) and Paul," said Hornish, who caught up with Till during the NASCAR Nationwide Series race last weekend at Mid-Ohio Sports Car Course. "With Paul and me, there's a lot of knowledge of racing that will go into it. I still have a lot of feelings that the IndyCar guys feel as far as the pressures in the championship, keeping emotions in check and what you want out of the race. I think that's one of the things had makes me credible is still living the life of a professional race car driver."
Hornish, who won Verizon IndyCar Series titles in 2001 and 2002 for Panther Racing and '06 with Team Penske, is competing in a limited Nationwide Series schedule this season. In seven starts, he has a victory at Iowa Speedway and three other top-five finishes for Joe Gibbs Racing. He was the series' championship runner-up in 2013.
"This is an opportunity to get my feet wet," said Hornish, who earned 19 victories among 47 podium finishes in 116 races over eight seasons. "You also walk that fine line of when are you more the TV guy than you are the actual driver. While I really enjoy what I'm doing, I'm looking forward to getting back to an IndyCar race."