Tongan international second row Lokotui makes his debut for the club having flown into the country last Sunday.
There is also a first start of the season for Ryan Mills, the England U20 international, following close season knee surgery.
Gloucester have won one and lost one from their two matches in the competition so far this season, so the game at Franklin's Gardens is a must win if the club is to have a chance of progressing to the semi final stage.
Forwards Coach Carl Hogg knows that Gloucester face a challenge, but will be up for the task in hand.
"We're looking to be successful in every competition, and we're obviously looking to win the game at the weekend.
"It's a competitive group and we've got it all to do. We've got Saints away and then Bath at home, so it's tough. But we go to Franklin's Gardens in good heart and will be looking to go up there and perform at our best.
Gloucester will field some of their best up and coming young talent alongside some experienced first teamers, and Hogg feels it's the right opportunity for them.
"The LV= Cup is a competition where you can take a look at some of our younger players. Our senior players can also get some game time and help bring on our youngsters.
"That's key not just for this season, but also going forward. Saints are big and physical and always go well at Franklin's Gardens. It will be a stern test but one we're looking forward to."
Martyn Thomas; Steph Reynolds, Henry Trinder, Tim Molenaar, Shane Monahan; Ryan Mills, Dave Lewis; Yann Thomas, Koree Britton, Dario Chistolini; Lua Lokotui, Elliott Stooke; Peter Buxton (capt), Andy Hazell, Gareth Evans
Tommaso d'Apice, Dan Murphy, Tom Heard, Tom Savage, Ross Moriarty, Jimmy Cowan, Mike Tindall, Rob Cook