Vizcaino, 33, would step into the veteran right-handed setup role vacated by LaTroy Hawkins, who signed with the Yankees during the weekend. Vizcaino struck out 62 in 75 1/3 innings last season, and has fanned 431 in 485 1/3 career innings with the Athletics (1999-2001), Twins (2002-2004), White Sox (2005), Diamondbacks (2006) and Yankees (2007).
Bean Stringfellow, Vizcaino's agent, said his client hasn't committed to the Rockies and a physical hasn't been scheduled, but they have been in negotiations. The Rockies' offer is believed to be sronger than that of the other team pursuing Vizcaino, the Pirates.
"If he were to sign with Colorado, I certainly do think there is a real good opportunity for him," Stringfellow said. "In effect, he and Hawkins would switch places."
The Rockies remain close to signing right-handed pitcher Kip Wells and left-hander Mark Redman, but those have yet to be completed.
By non-tendering outfieler Sean Barker and pitcher Darren Clarke -- both re-signed with the club on Minor League deals -- the Rockies have four open spots on their 40-man roster, so they'd still theoretically have room to sign another player.
The team needs a left-handed reliever to work earlier in the game than Brian Fuentes, who heads into the season as the primary lefty setup man.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.