Yussuf missing for Brewers Burton boss Gary Rowett will be without striker Adi Yussuf for Port Vale's trip to the Pirelli Stadium. The 20-year-old missed Saturday's 4-1 defeat to Gillingham with a groin injury he sustained in training recently and is expected to be out for a few weeks to come. The Brewers, who are currently sixth in the league, were unbeaten in eight games before coming up short against the Gills at the weekend. Rowett's side will be hoping for a swift return to winning ways on Tuesday but face stiff competition from a free-scoring Port Vale outfit who have 10 goals in their four outings this month. Five-goal striker Calvin Zola finally overcame a hamstring problem to make his first start since September 29 on Saturday and made it through the game unscathed. He is expected to lead the line again. Adam Yates is a major doubt for the visitors. The right-back suffered a knee injury in training which meant manager Micky Adams was only able to name six substitutes for Saturday's 4-1 victory against Wycombe, and he is unlikely to recover in time to face the Brewers. Yates joins captain Doug Loft and Ryan Burge on the sidelines. Burge will remain unavailable for a further two weeks with a knee problem, while Loft continues to struggle with a calf injury. Darren Murphy made his first competitive start for Adams' men in the victory against the Chairboys on his return from a series of hamstring injuries and he is in line to retain his place alongside Chris Shuker in a new-look central midfield. Tom Pope, who has now scored 15 goals in 16 matches, will lead the line for the Valiants as they bid for their sixth successive away win.