The good news for Kubina and the Leafs is that the injury will not require surgery, which would have kept him out of the lineup for a significant period of time.
Kubina suffered the strain in Monday night's 2-1 shootout win over Florida.
Kubina signed a US$20-million, four-year contract with the Leafs over the summer, one of Toronto's key off-season additions. He's the most significant in a long line of injured Toronto defencemen, joining Andrew Wozniewski (shoulder), Carlo Colaiacovo (head), Staffan Kronwall (ankle) and Brenden Bell (foot).
Tough guy Wade Belak will likely revert back to defence for Thursday's game at New Jersey after playing forward in the last three games, joining a blue-line that still has Bryan McCabe, Tomas Kaberle, Hal Gill, Ian White and Jay Harrison.