Oscar Cortes suffered a "severe" muscle injury against Kilmarnock and could be out long-term for Rangers, Philippe Clement has confirmed.

The winger limped off in the midweek win at Rugby Park and appeared to be clutching his hamstring.

Cortes - signed in January on loan from Lens with a purchase option - is set to face a lengthy spell out injured with surgery a possibility to correct the issue.

However, no decision has been made on whether Cortes will have an operation or not with Rangers chiefs in discussions with Lens - Cortes' parent club - and the player visiting specialists.

On Rangers TV, Clement confirmed: "In one way not good that Oscar has a serious injury, so he will be out for a longer time.

"It's a really strange one with the action that he did to have a severe injury like that.

"We need to look at that in the next couple of days what to do with it, operation or not.

"Also to be in contact with Lens because we are not only deciding about that of course.

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"That's a blow for him, the team, for all of us because he was doing really well."

Meanwhile, Abdallah Sima is set to return to training on the grass next week - albeit without a football.

“He’s good. Getting better and better. He’s on schedule," said Clement of Sima's condition.

“I don’t want to put a timescale on that, it’s a little too early.

“But next week for the first time he’s going to go on the grass for the first time without the ball. So that’s his normal programme."