Meanwhile Thorley, at 17 years and 59 days old, will become the youngest Gloucester player since the game went professional, beating Billy Burns who was aged 17 years and 130 days when he played at London Irish, also in the LV= Cup in February 2012.
Thorley, a pupil at Cheltenham College and who also plays for Stow Rugby Club, is one of the brightest young talents in the club's Junior Academy and a member of the England U18 squad.
Also, making their first starts of the season are Gareth Evans, Dan George, James Gibbons, Steph Reynolds and second row Tom Hicks who moved to Gloucester from the Saints in the summer.
Back row forward Ross Moriarty is named in the first team squad for the first time since recovering from shoulder surgery following England U20s Junior World Championship triumph. He will start on the bench.
And Dean Close School fly half Lloyd Evans, a regular in Gloucester's A League side this season is also named amongst the replacements.
Speaking to the local media this week, Director of Rugby Nigel Davies stressed that making full use of his squad is the correct way to proceed over the next few matches.
"Over the next three games, the two LV= Cup friendlies and the Japan fixture, we'll rotate the squad, field strong teams in all games, be competitive and gain some momentum in to the next block of Premiership games.
"Using the whole squad produces healthy competition for places, means that our injury rate is 20% better than it was this time last year, and will hopefully bring about dividends when we need to bring players in, as they'll have been playing at first team level.
"We've got a reasonable record against Northampton. They're a very good team, they play a good brand of rugby and are playing with a lot of confidence at the moment.
"It's a great opportunity for us. We're frustrated coming off last weekend's performance, because we thought we'd done enough to win. We've just got to be more clinical."
Martyn Thomas; Charlie Sharples, Ollie Thorley, Mike Tindall, Steph Reynolds; Freddie Burns (capt), Tavis Knoyle; James Gibbons, Dan George, Shaun Knight; Will James, Tom Hicks; Matt Cox, Matt Kvesic, Gareth Evans
Koree Britton, Yann Thomas, Tom Heard, Jonny Hill, Ross Moriarty, Reece Boughton, Billy Burns, Lloyd Evans