The Germany international has impressed off the bench twice since his move from Schalke, and could be deployed on the left flank if Bale plays down the middle.
"He's made an immediate impact in the team in both games," Villas-Boas said of the £1.25million midfielder.
"Lewis offers further options playing from the channels coming in. We haven't seen him in this position yet, but he finds comfort in that position because he played it before for Mainz.
"At the moment he's playing fantastically well. Hopefully we will continue to see him progress."