Walcott had been a doubt for the Premier League game after a succession of niggling injuries but after playing 90 minutes against Olympiacos in Athens, he has declared himself fit.
Midfielder Abou Diaby could also be available following a groin problem and Alex Song returns from suspension.
Emmanuel Eboue and Tomas Rosicky (both hamstring) miss out while
strikers Nicklas Bendtner (groin) and Robin van Persie (ankle) remain sidelined along with Gael Clichy (back) and Johan Djourou (knee).
Kick-off at Anfield is at 4pm.
Gunners (from) Almunia, Traore, Vermaelen, Gallas, Sagna, Song, Fabregas, Denilson, Nasri, Arshavin, Walcott, Mannone, Eduardo, Ramsey, Silvestre, Vela, Wilshere, Senderos, Diaby.