The Bristol trio of right-wing Lee Best, left-wing Brendon Daniel and openside Michael Lipman all make their bows after departing the relegated Shoguns.
Elsewhere, former London Wasps scrum-half Martyn Wood starts and Samoan No.8 Isaac Feaunati features against his old team after leaving Headingley, while there are also debuts for new signings Rob Fidler (lock), David Flatman (loosehead prop) and Duncan Bell (tighthead prop).
Springbok centre Robbie Fleck has not yet arrived at the club due to Currie Cup commitments back home, and the club are also without their host of World Cup stars, including the centre trio of Mike Catt, Kevin Maggs and Mike Tindall, as well as captain and lock Danny Grewcock.
Australian Chris Malone starts at fly-half after being recalled from a loan spell at Bristol following Catt's England World Cup inclusion, while Olly Barkley starts at inside centre.
Coach Connolly said ahead of the game: "Losing Catty leaves us with a massive challenge. However, we have tried a number of combinations over the pre-season and are looking forward to the trip to Headingley.
"Leeds are a very good side, they have a big pack and have the likes of Phil Christophers, Dan Scarbrough and David Rees in their backline. Like us, they have a number of new faces this season – it will be a tough game."
Bath: 15 Matt Perry, 14 Lee Best, 13 Alex Crockett, 12 Olly Barkley, 11 Brendon Daniel, 10 Chris Malone, 9 Martyn Wood, 8 Zak Feaunati, 7 Michael Lipman, 6 Andy Beattie, 5 Rob Fidler, 4 Steve Borthwick, 3 Duncan Bell, 2 Jonathan Humphreys (captain), 1 David Flatman.Replacements: 16 Hentie Martens, 17 Lee Mears, 18 Matt Stevens, 19 Robbie Kydd, 20 Jamie Williams, 21 James Scaysbrook, 22 Scott Gray.
Kick-off: 14.30 BST (13.30 GMT)