He elected to play baseball in college instead and was subsequently drafted three years later by the Seattle Mariners in the second round.

[6] He started six games and went 2-3 with a 3.24 ERA, which included going 7.1 innings in his debut on September 5, allowing no earned runs with six hits.

Hanson pitched the Opening Day game of the 1991 season, facing the California Angels.

He was traded on November 2 along with Bret Boone to the Cincinnati Reds for Bobby Ayala and Dan Wilson.

In his only season with the Reds cut short due to the strike, he went 5-5 on 21 starts with a 4.11 ERA with 101 strikeouts to 23 walks.

He went 15-5 that year while having a 4.24 ERA that saw him strikeout 139 batters with 59 walks in 186.2 innings and garner his only All-Star selection.