Hornish is a three-time champion of the Verizon IndyCar Series and a former winner of the Indianapolis 500. He has three career Nationwide Series victories with Team Penske and Joe Gibbs Racing, and 131 starts in the headline Sprint Cup division. His career-best fourth place finish came with Team Penske in 2011 at Pocono (Pa.) Raceway.
He was left without a ride at the end of last season when sponsorship failed to materialize, despite finishing a strong second in the Nationwide Series championship standings. He has run an extremely limited schedule with JGR this season.
Ambrose announced recently that he will return to his native Australia in 2014 to drive in the Australian V8 Supercar Series for a new team co-owned by Penske and Aussie Dick Johnson.