From ChicagoBlackhawks.com: (link)

The ceremonial first puck prior to the Sunday night’s Blackhawks game vs. the Edmonton Oilers will be dropped by actor William Petersen from the hit show "CSI: Crime Scene Investigation." Game time is 6 pm. at the United Center.

A native of Evanston, Illinois, Petersen is best known for his role as Gil Grissom on the hit series, CSI; Crime Scene Investigation. His film credits include: Amazing Grace and Chuck, Cousins, Young Guns II, Hard Promises, Passed Away, Fear, Kiss the Sky, The Skulls and The Contender.

Petersen trained for his career in acting in Chicago at the Steppenwolf Theater Company.