Allen will make his 100th starting appearance for Tigers since joining the club in the summer of 2009.
Deacon, who made his 250th Tigers appearance in the opening-day win over Worcester Warriors, sat out the fixtures against Bath Rugby and Newcastle Falcons but is fit to return to the forward pack.
Director of rugby Richard Cockerill also recalls Tom Youngs, Dan Cole, Geoff Parling, Julian Salvi and Niall Morris to the starting line-up this week after rotation for the Falcons fixture last Saturday.
Cockerill has confirmed that centre Manu Tuilagi suffered a chest muscle injury in the bonus-point win over Newcastle Falcons last week but will not require surgery. Vereniki Goneva moves to centre in his absence and Blaine Scully is on the wing as Morris returns at full-back.
Leicester Tigers (v Exeter Chiefs, Sandy Park, Sunday 2pm)
15 Niall Morris
14 Blaine Scully
13 Vereniki Goneva
12 Anthony Allen
11 Adam Thompstone
10 Toby Flood (c)
9 Ben Youngs
1 Logovi’i Mulipola
2 Tom Youngs
3 Dan Cole
4 Louis Deacon
5 Geoff Parling
6 Ed Slater
7 Julian Salvi
8 Jordan Crane
Replacements
16 Neil Briggs
17 Boris Stankovich
18 Fraser Balmain
19 Graham Kitchener
20 Jamie Gibson
21 Sam Harrison
22 Owen Williams
23 Dan Bowden
Exeter Chiefs: 15 Phil Dollman, 14 Ian Whitten, 13 Jason Shoemark, 12 Sam Hill, 11 Tom James, 10 Gareth Steenson, 9 Haydn Thomas; 1 Brett Sturgess, 2 Jack Yeandle, 3 Hoani Tui, 4 Dean Mumm (c), 5 Damian Welch, 6 Tom Johnson, 7 James Scaysbrook, 8 Dave Ewers. Replacements: 16 Chris Whitehead, 17 Ben Moon, 18 Carl Rimmer, 19 Tom Hayes, 20 Ben White, 21 Dave Lewis, 22 Henry Slade, 23 Matt Jess
