This news release just arrived from the Lightning. No confirmation on the ACL, but the fact that the team is acknowledging surgery is likely would seem to square with the early reports. Here's the release:

TAMPA BAY - Tampa Bay Lightning center Jeff Halpern has suffered a right knee injury that is expected to require surgery, it was announced by Lightning Executive Vice President & General Manager Jay Feaster. Halpern sustained the injury during the third period of Team USA’s 5-4 loss against Canada at the IIHF World Championships in Halifax, Nova Scotia yesterday. Halpern is serving as captain of Team USA at the tournament.

            Under the direction of the Lightning medical staff, Halpern will travel to Washington, D.C. today to see Dr. Benjamin Shaffer, team physician for the Washington Capitals. Dr. Shaffer performed surgery on Halpern’s left knee in 2002 to repair a torn anterior cruciate ligament (ACL). More information will be available following the results of an MRI and the evaluation by Dr. Shaffer.