This season the NHL has adopted 3-on-3 overtime instead of the usual 4-on-4. They won't admit it flat-out, but this is a sure fire way to limit the number of games that end in a shootout. The coaching staff has been hashing out who will be on the ice for the overtime, and this pre-season they'll get a chance to tinker with the lines.
The Blues will be participating in three overtime test runs, regardless of what the score is at the end of regulation. To see how the new format works, the NHL has named several pre-season games as tester games. The three that the Blues will be participating in are September 22nd's game against the Columbus Blue Jackets at Nationwide Arena, September 26th's game against the Chicago Blackhawks at the United Center, and October 1st's game against the Hawks at Scottrade.
None of these games will be televised as of now, so we'll have to experience the overtime via the airwaves.