Siani attended Villanova University, where he not only played football but also excelled in baseball. Between 1968 (when he was still in high school) and 1972, Siani was selected on four occasions by three Major League organizations (the New York Yankees, the Los Angeles Dodgers, and the Texas Rangers), but he never signed.[1]
Siani was the first round draft choice of the Oakland Raiders. In 1972, his first year in Oakland, he set multiple rookie team records for receiving and finished as the runner-up to Franco Harris as NFL Rookie of the Year. He played for the Raiders through 1977, appearing in 74 games with 32 starts, and he caught 128 passes for 2,079 yards and 13 TDs. With the Raiders having a surplus of wide receivers, the team traded Siani along with a 1979 third-round selection (72nd overall–traded to Houston Oilers) to the Colts for Raymond Chester and a 1979 second-round pick (33rd overall–traded to Tampa Bay Buccaneers for Dave Pear) on July 21, 1978.[3][4] Siani played three seasons with the Colts before finishing his NFL career in 1980.[5]