Eddie, the 24-year-old back-rower, and Dewey, the Scotland international centre, have been sidelined due to shoulder and ankle injuries respectively.
On welcoming back the duo, Warriors head coach Sean Lineen said: "Competition for places is already very intense at Glasgow and the return of James and Rob will fuel that even further.
"Everyone is challenging each other at training so it's great to have two quality players back and available for selection."
Glasgow Warriors team to play Leinster in the Magners League on Friday 8 January (kick-off 8pm)
15 Bernardo Stortoni
14 DTH van der Merwe
13 Max Evans
12 Graeme Morrison
11 Thom Evans
10 Dan Parks
9 Chris Cusiter
1 Jon Welsh
2 Dougie Hall
3 Moray Low
4 Alastair Kellock CAPTAIN
5 Richie Gray
6 Kelly Brown
7 John Barclay
8 Johnnie Beattie
Substitutes
16 Fergus Thomson
17 Kevin Tkachuk
18 Dan Turner
19 James Eddie
20 Colin Gregor
21 Ruaridh Jackson
22 Rob Dewey
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland