Morelos has made 36 appearances for Rangers in all competitions this season, with the Colombian striker grabbing 15 goals and 12 assists in the process.
The 24-year-old has been in fine form since Christmas, scoring eight goals in his last 12 games for Rangers, having managed just seven in his first 23 games of the season.
Rangers, having gone undefeated en route to winning the Scottish Premiership title this season, will look to maintain their unbeaten streak when they clash against Celtic on Sunday.
Miller stated that Rangers lack the physicality that Morelos brings to the pitch when he is not playing.
The former Rangers striker suggested that Morelos is a big contributor to the Gers with his ability to terrorise and tire defences as well as his flexibility to play against a back-four or a back-five.
“He’s run some really good defences ragged over the years, particularly in Europe, and I think that’s where people take notice, including teams on the continent”, Miller told Sky Sports News.
“He seems to be refocused.
“It’s been a wonderful year for the club and him. He’s not scoring as many goals as he has done maybe, but he is a big contributor to that team.
“When he is not playing, they miss that physical element up front because he can work a back-four, back-five whatever it is – he has terrorised some big players over the last two or three years.”
Morelos will hope to end his 14-game run without a goal against Celtic when Rangers travel to Celtic Park to face the Hoops on Sunday.
