The 33-year-old flanker will retire from rugby after tomorrow night's game, which is his 146th for the province.
O'Connor represents the only personnel change to the Forwards from the team who drew to Treviso last weekend. He is joined in the back row by Andrew Browne and Eoin McKeon, who moves to Number 8.
On his return from injury, 22-year-old Eoin Griffin is named at outside centre for the last game of the 2012/13 season. This change sees the season's record try scorer, Danie Poolman, move on to the right wing.
On the bench, Adrian Flavin is named at replacement hooker and is in line to make his 142nd and final appearance for Connacht - his team for the last seven years.
Connacht currently occupy 8th place in the RaboDirect PRO12 table, and while a win tomorrow night would equal the best ever finish achieved last year, it would also mean a record number of wins in the league to go with a best away record so far.
Connacht XV
15. Gavin Duffy (captain)
14. Danie Poolman
13. Eoin Griffin
12. Brian Murphy
11. Fetu'u Vainikolo
10. Dan Parks
9. Kieran Marmion
1. Brett Wilkinson
2. Ethienne Reynecke
3. Ronan Loughney
4. Michael Swift
5. Mike McCarthy
6. Andrew Browne
7. Johnny O'Connor
8. Eoin McKeon
Replacements (from): Adrian Flavin, Rodney Ah You, JP Cooney, Mick Kearney, John Muldoon, Mata Fifita, Paul O'Donohoe, Miah Nikora
Unavailable due to injury: Denis Buckley, Willie Faloon, Eoghan Grace, Robbie Henshaw, Dave McSharry, Frank Murphy, George Naoupu, Dave Nolan, Kyle Tonetti, Nathan White.
It's all happening at the Sportsground this Friday night as we celebrate Eric Elwood's last ever game as Head Coach. To find out more on the activities planned click here.
Tickets are selling fast so don't miss out on this special event and come up to the Sportsground to bid farewell to Eric, Johnny and Flav. Tickets available from the Connacht Rugby office and ticketmaster.ie.
Connacht Rugby v Glasgow Warriors At Sportsground, 7.45pm
Referee: George Clancy (IRFU, 55th competition game)
Assistant Referees: Paul Haycock, John Carvill (both IRFU)
Citing Commissioner: John Cole (IRFU)
TMO: Seamus Flannery (IRFU)
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland