Thomson is one of five changes to the Boro team that drew 3-3 at Ipswich in midweek and Mowbray knows that the fight to avoid relegation to League One could be officially won today.
Thomson replaces the injured Matthew Bates in midfield, while Andrew Davies has been recalled to the heart of the defence in the absence of the sidelined Seb Hines.
Barry Robson and Rhys Williams are also starters instead of Tarmo Kink and Julio Arca, while Andy Halliday's reward for a star showing as a substitute at Portman Road is his first start under Mowbray.
MIDDLESBROUGH (4-4-2): Smith; McMahon, McManus, Davies, Bennett; Robson, Williams, Thomson, Taylor; Halliday, McDonald. Subs: Coyne (gk), Haas, Kink, Tavares, Smallwood, Grounds, Flood.
BARNSLEY (4-4-2): Steele; Hill, McShane, Shackell, Trippier; Haynes, Doyle, Mellis, Butterfield; Gray, Harewood. Subs: Preece, McEveley, Foster, O'Brien, Arismendi, Taylor, Clark.
Source: Northern Echo
Source: Northern Echo