The London giants suffered a 1-0 loss to Les Parisiens in the first leg at the Emirates Stadium and have work to do to make the final in Munich.
Ahead of the game, they have received a massive boost on the injury front.
Jurrien Timber missed the recent Premier League loss to Bournemouth with an injury, but he has recovered in time to feature in team training.
The Dutchman has been joined by Riccardo Calafiori. The Italian star is back in the mix after overcoming a knee injury sustained in March.
Timber could be drafted straight into the starting XI tomorrow but it is unlikely that Calafiori will do so. He could be restricted to a cameo.
With the return of Thomas Partey due to suspension, Arsenal have been handed another boost for the return leg at Parc des Princes tomorrow.