The Ospreys could be without the services of Dan Lydiate and Nicky Smith throughout the first month of 2019.
The pair have both missed recent matches, Lydiate not featuring for the Ospreys since the win over Connacht at the October after suffering an elbow injury on international duty in November, Smith suffering an ankle injury in the Challenge Cup win over Stade Francais at the Liberty Stadium earlier this month.
Asked after Sunday’s Dragons match about their likely availability, Clarke said:
"They are long-termers so they won't be in the picture for a few weeks yet. They will be out for a minimum of four to six weeks.
"Dan has suffered a recurrence of his injury so they are looking at that."
