Finley, who will turn 42 on March 12 and has played in 18 Major League seasons, has 303 home runs and 320 career stolen bases, and is one of six players in history to surpass 300 in those categories.
Last season, Finley hit .246 with six home runs and 40 RBIs in 139 games as the Giants' primary center fielder. Willy Taveras is the Rockies' projected starter in center and erstwhile starter Cory Sullivan is competing for playing time.
Finley, who was scheduled to arrive in Tucson on Saturday night and will be in uniform on Sunday, adds another dynamic as a player who still provides speed and bats left-handed.
"It goes to putting us in even better position with our depth," Rockies manager Clint Hurdle said. "He still has some things he wants to [get] accomplished."
Rockies left-handed pitcher Jeff Francis said Finley was difficult to pitch to last season, and can provide the Rockies with needed experience in 2007.
"I'm excited about that," Francis said. "On a team with a core of guys that are really young, to have a guy like that come in, he's a good guy to have around. He knows what to do."
Finley has a .272 career batting average in 2,540 Major League games with seven teams. Finley, a .314 career hitter at Coors Field, has played for all of the teams in the National League West except for the Rockies.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.