[3] At Edmonds, Riggan took a line drive to the head and wore a batting helmet while pitching for the following year.

He was selected in the thirteenth round of the 1995 Major League Baseball draft by the Florida Marlins but did not sign.

He subsequently landed a contract with the New York Mets after seeing an ad in The Wenatchee World for an open tryout in Yakima, Washington.

[4] Riggan was called up to the majors for the first time in August 2000 following an injury to Mets reliever John Franco.

The Mets intended to add Eric Cammack to the roster but he was unable to make it due to bad weather in Norfolk, Virginia.

He made his Major League debut on August 29, pitching two scoreless relief innings against the Houston Astros.

[12] In spite of that, on December 11, 2001, he was traded to the Cleveland Indians along with Alex Escobar, Matt Lawton and players to be named later in exchange for future Hall of Famer Roberto Alomar, Mike Bacsik and a minor leaguer.

[16][17] On August 15, he once again returned to the roster along with pitcher David Riske and appeared regularly in relief for the remainder of the season.

[24] In June 2003, Riggan was granted a release by the Mets to sign a seven-figure contract with the Hanshin Tigers for the remainder of the 2003 NPB season and the entirety of the following year.

[26] In his second season with Hanshin, Riggan blew out his elbow and underwent Tommy John surgery on June 29, 2004.