Philippe Clement revealed a specialist is looking into Oscar Cortes’ muscle injury, with no time frame yet for the Rangers winger’s return.

The 20-year-old Colombia international hit the ground running after joining the Light Blues on loan from Lens last month, with the Govan club having an option to buy in the summer.

Cortes scored his first goal for Rangers in the 5-0 thumping of Hearts at Ibrox last weekend but had to come off during the 2-1 win over Kilmarnock at Rugby Park on Wednesday night which kept the Light Blues two points clear of Celtic at the top of the cinch Premiership.

The Belgian boss confirmed striker Kemar Roofe and midfielder Ryan Jack would return to the squad for the home game against Motherwell on Saturday, but on Cortes he said: “Oscar will be out, I don’t know how long.

“We are looking into that with the doctor and specialist.

“It is a muscle injury, but I cannot say much more at the moment.

“I don’t want to speak about a half-empty glass.

“I am focused now on the players who are available for this game, because otherwise I would have lost a lot of energy in the last couple of months and that is useless.

“It is a pity for him and the team, yes, it is an opportunity for another player to show it and to do it, it works like that.”

Clement reiterated the importance of the squad which was trailing Celtic by seven points when he took over from Michael Beale in October.

He said: “In these four months together, every member of the squad has raised their level.

“Not only physically, but in every sense, technically and tactically, so they know what to do.

“In that way it has been really important to work with everybody and not be focused on 11, 14 or 15 players, but on everybody and we will continue like that.”

The hard-fought win over Killie extended Rangers’ winning run to 11 games, but Clement revisited the match with a view to a possible Gers penalty, while also referring to the practice of players trying to run, turn and tackle with their hands behind their back due to the fear of the ball striking them.

Killie wide-man Danny Armstrong scored from the spot in the 11th minute after his cross hit the arm of Gers midfielder John Lundstram inside the box.

Clement wondered why Rangers did not also get a spot-kick late in the game when Killie defender Lewis Mayo appeared to handle the ball inside the area.

He said: “I hope there can be more clarity about things in the future. I know there are decisions made in a grey zone.

“I don’t think for the handball rule it has become easier for referees or the VAR. It has become more difficult with the rule and the way it is decided by UEFA and FIFA.

“My job is to explain to my players what is hand ball or not. If they come on to the pitch feeling there is an injustice then we have a problem.

“I don’t say that was the case, but it needs to be really clear what is hand ball or not. I don’t think it is good for the game if all the players running around with their hands on the back, like you see now.

“Even then when your hand is like that (out) it is sometimes hand ball. It is not good for the game if players run around like penguins.”