The German has not scored since January 1 2016 and has only been on the pitch for 92 minutes in the Championship this season.
Much of that time on the sidelines has been down to the form of Scott Hogan and latterly Lasse Vibe but the big frontman has also been struggling with a back complaint.
Smith said: “He's had an injury. It's been very difficult for him. We had Scott Hogan scoring goals for fun and Lasse Vibe has continued what Scott was doing so it's tough for him to get game time.
“He's had a nasty injury with his back. He's on the bench ready to be called for.”
Hofmann has made seven starts and 28 substitute appearances in all competitions since signing for the Bees from Kaiserslautern in 2015 for £1.2million.
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