Lee Carsley has been in charge of the Championship side since September.
The Bees have been without a permanent boss since Marinus Dijkhuizen was dismissed after just nine matches back in September. The Dutchman oversaw just two wins during his time at the helm, and was replaced by former Everton midfielder Lee Carsley.
According to BBC Sport at the time of Dijkhuizen's sacking, Carsley was due to take charge of the team until the end of the season.
Despite the 41-year-old guiding the Griffin Park outfit to five wins from nine games, the club have decided to appoint a new man, although it will be Carsley who takes charge for today's game against Bolton (via the Evening Standard). Carsley's successor has been working wonders at the Bescot Stadium.
Saturday's victory over Bradford City has kept the Saddlers in the League One play-offs places. And a win against Shrewsbury on Tuesday could see the side move into the automatic promotion spots.
However, it appears that they will have to go up against the Shrews without Smith, who is now destined for Brentford.