The 26-year-old, who joined the club from Doncaster Rovers in 2012, struck Middlesbrough's leveller in the 2-2 draw at the DW Stadium.
Mowbray told the club's official website: "We have been trying to get George playing higher and back to how he did early last season.
"The signs are good and we're pleased with him. He's still got a bit to go, but we all saw in his first six months what a threat he can be and we've got to make sure he continues in that vein."
Middlesbrough currently sit 14th in the Championship table.