Bees boss Scott moved for Williams, who has also had spells with Colchester and Walsall this season, after Nathan Elder was ruled out for the rest of the season with a fractured cheekbone and eye socket.
Barnet boss Ian Hendon is again likely to name Jake Cole in goal as his side look to keep up their good form away at Brentford on Tuesday.Cole joined last week from QPR and featured in the 3-1 win over Chester on Saturday after Lee Harrison (groin) was ruled out for a month.
