The Dutch winger is now in a race against time to be fit for Wednesday's crucial Champions League qualifying clash against Elfsborg.
"We have a bit of a sweat on for Wednesday night to see how he is," PA quotes Lennon as saying.
"He jarred his ankle. It was a total accident, he clipped Mihael Kovacevic's Achilles and it has twisted.
"You can see what Derk brings to the team, that pace and balance on the left. He looked a real threat in the first half."
The Bhoys take a 1-0 lead into the second leg in Sweden.