The Welshman provided the cross that helped Joel Piroe open the scoring for Leeds in their 3-0 win over Watford at Elland Road on Saturday.
James has scored just four times and laid on eight assists in 46 appearances for Leeds and has often been a frustrating figure for Whites fans.
McCormack admitted that he can understand some of the fan reaction to James as everyone is aware of his talent and ability and he could do much more for Leeds than he has produced thus far.
The former Leeds captain wants the winger to have a little more faith in his ability to take on opposition defenders and add more consistency to his talent.
The Scot said on BBC Radio Leeds: “You can understand some of the fans’ frustration because you know fine well what’s in him and what he can go and produce.
“You just want to see a little bit more more often.
“Saw it with [Crysencio] Summerville quite a bit in the first half and in the second half – going at people, beating people and creating things.
“You just want to see Dan James have a little bit more belief in his own ability to really go and take it to the opposition.
“It’s there, he can do it, everyone saw it in the past and it’s about doing it consistently.”
Leeds now sit in sixth place in the Championship and are eight points off the top two automatic promotion slots.