The youngster spent much of last season on loan, but this summer has been given his chance to impress in the first team and has grasped it with both hands, which has impressed his boss.
Martinez said, “Luke Garbutt is a phenomenal youngster and someone who has earned the place to be in the first team. Last season he went out on loan and we followed him closely and he did really well.
“He’s someone who can compete for a place in the first team. He’s got great people in front of him and he can learn a lot. He has played really well with the Under-21s at England level and he’s got a great future so he’s great to have in the squad because it’s very difficult.
“Garbutt has been very impressive. One of the most impressive young players that we have had this pre-season.”