Leicester Tigers give league debuts to five summer signings in the opening fixture of the Aviva Premiership season at London Irish this Sunday.Summer arrivals Peter Betham, Greg Bateman, Mike Williams, Mike Fitzgerald and Lachlan McCaffrey all run out for the first time in a competitive fixture for the club, with Australia international Betham and second-rower Fitzgerald starting an Aviva Premiership game for the first time in their careers.   Back-rower Opeti Fonua and young scrum-half Ben White are also looking to make their first Tigers appearance from the replacements.   Fonua is included in the squad after reporting back from international duty with Tonga in time to play a part in the Kings of the North victory against Sale Sharks last weekend. Marcos Ayerza remains on World Cup duty with Argentina, while the other World Cup players have reported back to Welford Road and have been rested for this weekend.   Mathew Tait leads the team in the absence of club captain Ed Slater.   There is a timely return for Owen Williams who is recalled to the matchday squad for the first time since suffering a knee ligament injury in the Cup victory at Cardiff Blues in February.   Freddie Burns, though, is ruled out after an injury in the fixture against Sale Sharks last weekend was confirmed as a broken jaw. Director of rugby Richard Cockerill has confirmed that the injury is likely to sideline Burns for 6-8 weeks. Tommy Bell starts at fly-half. Tigers will wear the dark alternate kit at the Madejski Stadium this Sunday. This match is not scheduled for live TV coverage, but supporters can keep up to date with Tigers social media and the club website throughout the afternoon.   Leicester Tigers (v London Irish, away, Sunday 3.15pm) 15 Mathew Tait (c)   14 Adam Thompstone   13 Peter Betham   12 Seremaia Bai   11 Matt Smith   10 Tommy Bell 9 Sam Harrison   1 Logovi’i Mulipola   2 Greg Bateman      3 Fraser Balmain    4 Mike Williams    5 Mike Fitzgerald  6 Tom Croft  7 Lachlan McCaffrey  8 Laurence Pearce   Replacements 16 Harry Thacker   17 Riccardo Brugnara   18 Tiziano Pasquali   19 Sebastian de Chaves    20 Opeti Fonua 21 Ben White    22 Owen Williams   23 George Catchpole   London Irish: 15 Andrew Fenby, 14 Alex Lewington, 13 Tom Fowlie, 12 Eoin Griffin, 11 Topsy Ojo, 10 Chris Noakes, 9 Brendan McKibbin; 1 Tom Court, 2 David Paice, 3 Halani Aulika, 4 George Skivington (c), 5 Matt Symons, 6 Jebb Sinclair, 7 Luke Narraway, 8 Rob McCusker Replacements: 16 Gerard Ellis, 17 Tom Smallbone, 18 Leo Halavatau, 19 Eoin Sheriff, 20 David Sisi, 21 Scott Steele, 22 Shane Geraghty, 23 Fergus Mulchrone