Harris hasn't actually announced whether or not he's on Top Gear yet, but other rumors also put him in the cast. He would certainly be a valuable asset. The Chris Harris on Cars series shows he's an engaging host and adept at big slides in high-performance machines. Harris is also a talented writer, which could only help the show.
Beyond Evans, LeBlanc, and possibly Harris, speculation also suggests Nürburgring ace Sabine Schmitz could be a host. Those reports might be accurate because Schmitz was driving an Audi R8 V10 Plus when Evans lost his lunch at Mazda Raceway Laguna Seca. She has also been a regular guest on Top Gear with the previous trio.
Top Gear returns to the telly in the UK on May 8 for a 16-episode season. It's too soon to know about a US premiere, but Autoblog will keep you posted.