The Gunners were outclassed by Borussia Dortmund in their opening European game of the season and have now won only one of their last six matches.
This run, which has included three consecutive top-flight draws, has left Arsene Wenger's side seventh in the table and dampened some of the title-chasing enthusiasm that was prompted by their convincing Community Shield win over Manchester City.
The English champions were their opponents again last Saturday and Martin Demichelis headed in late on to deny Arsenal victory, after Jack Wilshere and Alexis Sanchez had turned around a first-half deficit.
Deadline-day signing Danny Welbeck hit the post in his debut at the Emirates Stadium, and missed several more chances in Germany on Tuesday, but Wenger is confident that the Londoners will see a more clinical version of the England international once he has broken his club duck.
Villa have been the surprise package so far this campaign, and indicated that their seven-point haul from their first three games was not misleading early-season form when they won at Anfield five days ago.
Such has been their strong start to the campaign that second-placed Villa can lose to Arsenal and still sit above them in the table, but Paul Lambert will be confident of claiming another top-four scalp.
Should Vlaar not pass a late fitness test, the Scot may see no reason to alter his starting XI and therefore Nathan Baker is in line to keep his place at centre-back, with Tom Cleverley continuing in midfield.
Lambert still has Christian Benteke and Libor Kozak to return and potentially improve his team, but both strikers are still weeks away from contention, while Joe Cole is another working his way back to fitness.
Wenger is also without his main forward, with Olivier Giroud out until Christmas, and so Welbeck will lead the line once more, but the Gunners boss also has injury concerns at the other end of the park.
Wenger may make the brave call to drop Mesut Ozil, who has struggled since returning to Arsenal after winning the World Cup with Germany and has Santi Cazorla and Alex Oxlade-Chamberlain pressurising his place.
The decision could be made for Wenger depending on the fitness of Wilshere, with the England midfielder having turned his fragile ankle on Champions League duty, but hopeful of featuring at Villa Park.
Arsenal have an excellent recent record against Villa - losing just three times in their last 31 meetings.
Possible starting lineups
Villa: Guzan; Hutton, Baker, Senderos, Cissokho; Westwood, Cleverley, Delph; Richardson, Weimann, Agbonlahor
Arsenal: Szczesny; Chambers, Koscielny, Mertesacker, Gibbs; Ramsey, Arteta; Cazorla, Wilshere, Sanchez; Welbeck
Sports Mole says: 1-1