The information comes from Kilmarnock's Austrian goalkeeper Daniel Bachmann.
Speaking to press in his homeland, the 24-year-old stressed the importance of the Colombian striker. He has netted 17 times in 29 appearances this season, while offering the club a different dimension in attack.
"If he is missing, they win little," he said.
However the forward has been sent off three times this campaign, the latest coming in the club's 1-0 league defeat to Aberdeen.
In the three games he has missed through suspension Rangers are yet to win.
"He's very vulnerable to provocation and of course Rapid can take advantage of that," said Bachmann.