The Lions have beaten top-half sides in the form of Nottingham Forest and Wigan Athletic in their last two games to climb to within two points of safety.
They face another this weekend, with Watford having moved up the table courtesy of rediscovering their scoring boots in a run of only one defeat in six matches.
Deeney, who has 21 goals to his name this season, scored a brace as the Vicarage Road outfit beat Sheffield Wednesday 4-1 last month to record their first away victory in 15 matches in all competitions.
He was also on the scoresheet in the 3-0 success over Leeds United in midweek, a result which took the Londoners to within eight points of the playoffs with a game in hand on the teams around them.
Watford boss Giuseppe Sannino is still without Forestieri and Battocchio, who is nearing a return to fitness, for their trip across the capital, where Mathias Ranegie and Lewis McGugan are pushing for recalls.
Former Liverpool and Manchester City star Albert Riera is likely to be preferred to Daniel Pudil at left-back again, as the Hornets go in search back-to-back victories on the road and a double over Millwall.
Possible starting lineups
Millwall: Forde; Edwards, Beevers, Dunne, Malone; Woolford, Upson, Bailey, Garvan, Martin, Maierhofer
Watford: Almunia; Anya, Ekstrand, Angella, Doyley, Riera; Faraoni, Murray, Abdi; McGugan, Deeney,
Sports Mole says: 2-1