James has played every game for the Tykes so far this season, having joined the Championship club on loan from Leicester.
"He's played every game for us and played extremely well," Murphy said.
"He's a huge boon in the locker room and on the field.
"He has an air about him, and not just because he's a great player, and he's played at the highest level, so he has that stature, it's also because of him as a guy and he oozes this confidence and ability to galvanise and push this group.
"I've spoken to Matty and his representative and he's enjoying his time here. And in January it will basically be up to Leicester City and what they want to do with him to see if we can try and get him for the back half of the season."