Teenage winger Chamberlain and 16-goal striker Barnard are sidelined by ankle injuries and are unlikely to play again this season.
Midfielder Morgan Schneiderlin (knee) and winger Lee Holmes (ankle) remain long-term absentees but boss Nigel Adkins has no new injury concerns.
Left-back Dan Harding and midfielder Adam Lallana overcame groin problems to play in Monday's 2-0 win over Hartlepool and came through unscathed.
Radhi Jaidi, Danny Butterfield, Richard Chaplow and former Brentford defender Ryan Dickson are pushing for recalls after dropping out against Pools.
Saints remain in the second automatic promotion spot on goal difference from Huddersfield and with a game in hand.
Source: PA
Source: PA