Stand-off Clegg has re-joined the Warriors on a deal until May 2017 and following five months with French Top 14 side Oyonnax, goes straight into the starting line-up to make his first appearance for the club since facing Leinster at the RDS last October.
Ashe starts at Number 8 after recovering from a shoulder injury, while Holmes is named amongst the replacements following a three-month spell on the sidelines with a foot injury.
Peter Murchie retains his place at full-back, with Lee Jones and Rory Hughes continuing on either wing.
Mark Bennett once again wears the Number 13 jersey, with Sam Johnson coming in for Alex Dunbar at inside centre.
Clegg starts at stand-off, with Duncan Weir away with Scotland, while Grayson Hart replaces Henry Pyrgos at scrum-half.
In the pack Gordon Reid and Fraser Brown once again start at loose-head and at hooker respectively, with Sila Puafisi coming in for Zander Fagerson at tight-head.
Leone Nakarawa moves from Number 8 back into the engine room to partner USA international Greg Peterson.
James Eddie comes in for Rob Harley at blind-side flanker, Simone Favaro replaces Chris Fusaro at open-side and Ashe completes the backrow.
BT Sport Scottish Rugby Academy Stage 3 centre Nick Grigg could make his debut for the club from the bench.
Glasgow Warriors head coach Gregor Townsend said: "We're really looking forward to facing Leinster at a sold-out Scotstoun tomorrow night.
"We've had some great battles with them over the years and they have being playing well during the 6 Nations window.
"They have always set very high standards and continue to deliver a high level of performance, whichever team they put out on the field.
"We're delighted to welcome Rory (Clegg) back to the club and he goes straight into the side with Finn (Russell), Duncan (Weir) and Peter (Horne) away with Scotland and Gregor (Hunter) out injured."
Glasgow Warriors team to face Leinster on Friday 18 March at Scotstoun Stadium, kick-off 7.35pm, live on Sky Sports 3:
15. Peter Murchie (Captain)
14. Lee Jones
13. Mark Bennett
12. Sam Johnson
11. Rory Hughes
10. Rory Clegg
9. Grayson Hart
1. Gordon Reid
2. Fraser Brown
3. Sila Puafisi
4. Greg Peterson
5. Leone Nakarawa
6. James Eddie
7. Simone Favaro
8. Adam Ashe
Replacements
16. James Malcolm
17. Jerry Yanuyanutawa
18. Zander Fagerson
19. Scott Cummings
20. Tyrone Holmes
21. Ali Price
22. Nick Grigg
23. Glenn Bryce
Not available due to injury: Alex Allan (concussion), Mike Blair (concussion), Kevin Bryce (shoulder), Chris Fusaro (concussion), Ryan Grant (arm), Gregor Hunter (concussion), Pat MacArthur (glut / hamstring), Fergus Scott (shoulder) and Richie Vernon (shoulder).
Guinness PRO12 Warriors News
63x46.png){kind=logo}