Clarke admits the Swedish striker could decide to move on in the summer.
"He's been a vital member of my squad and he hasn't had the minutes on the pitch that maybe he has deserved. A lot of that is down to the fact that Lukaku and Long have had great seasons.
"Markus is a striker who likes to play in a central role and the other two got in front of him and didn't really give him a sniff to get in.
"He has waited patiently for his chance and he showed on Saturday that he's got the qualities and the determination to show everybody he is still a good player.
"I don't think the fact Markus hasn't played for us a lot this year is going to have a great bearing on what we decide to do with him this summer.
"We will sit down at the end of the season and have a chat. Markus will tell me what he thinks honestly, I'll tell him what I think honestly and then we'll try to move forward."