GSN is set to announce the third-season renewal of “High Stakes Poker,” sources said. The series has averaged about 360,000 viewers, which is significantly above GSN’s average prime-time viewership. The Monday night series boasts the only “cash game” on television-one in which players risk hundreds of thousands of their own pocket money rather than compete in a tournament, where players risk only a one-time entry fee. GSN declined to comment.