Tomkins: Will make his debut for Saracens on Sunday

The former Wigan rugby league star, who switched codes in November, will make take his first-team bow in the number 13 shirt at Vicarage Road.

Jamie George will captain a much-changed Sarries side that also includes a first-team debut for second row Eoin Sherriff and a first appearance of the season for Michael Tagicakibau.

Scott Spurling is in line for a full Saracens debut from the bench, as is academy wing Nathan Earle. Prop James Cleverly, who is on loan from Blackheath, is also among the replacements.

Blair Cowan will make his debut for Worcester after being selected at No. 8 as the Warriors also make a number of changes, with Josh Drauniniu and Sam Betty the only survivors from the starting line-up that faced Stade Francais in the Amlin Challenge Cup last time out.

Joe Carlisle is named at inside centre where he will combine with Fiji international Ravai Fatiaki, while Chris Pennell captains the team from full-back and Danny Gray and Jonny Arr form the half-back pairing.

In the pack, Richard Muagututia moves to openside flanker while hooker Chris Fortey is named in the front row.

"Blair has trained really well and has fitted into the club well. He is a robust character, a good ball carrier and strong addition to the group so we are keen to see him in action," forwards coach Phil Davies said of the recent signing from Cornish Pirates.

"We have made changes because you have to keep the whole squad going, you can't be successful with just 23 players. This cup game gives an opportunity for players to come in and put their hand up for more selections.

"Saracens will have players away on international duty, but they have such a strong squad and Academy process that we know it will be a strong team that they put out.

"We will go down to London and have a real go, we are looking forward to the game."

Saracens: 15 Duncan Taylor, 14 Kameli Ratuvou, 13 Joel Tomkins, 12 Adam Powell, 11 Michael Tagicakibau, 10 Nils Mordt, 9 Peter Stringer, 8 Jackson Wray, 7 Will Fraser, 6 Justin Melck, 5 Eoin Sherriff, 4 George Kruis, 3 Petrus du Plessis, 2 Jamie George (capt), 1 John Smit.

Replacements: 16 Scott Spurling, 17 Nick Auterac, 18 James Cleverly, 19 Hugh Vyvyan, 20 Tom Jubb, 21 Luke Baldwin, 22 Nathan Earle, 23 Ben Ransom.

Worcester: 15 Chris Pennell (capt), 14 Tom Arscott, 13 Ravai Fatiaki, 12 Joe Carlisle, 11 Josh Drauniniu, 10 Danny Gray, 9 Jonny Arr, 8 Blair Cowan, 7 Richard Muagututia, 6 Sam Betty, 5 Craig Gillies, 4 Ben Gulliver, 3 Oliver Tomaszczyk, 2 Chris Fortey, 1 Bruce Douglas.

Replacements: 16 Aleki Lutui, 17 George Porter, 18 James Currie, 19 Nile Dacres, 20 Matt Kvesic, 21 Ollie Frost, 22 Miles Benjamin, 23 Errie Claassens.