Martin, 25, has arrived in Florida, and he took his physical on Thursday and will report to Minor League camp Friday. Washington beat out the Mariners and Yankees for his services.
On Wednesday, team president Stan Kasten hinted to MLB.com that the Nationals were on the verge of announcing the signing of an older player from Latin America, but he did not say who it was.
"We made some signings that we haven't released yet," Kasten said. "We are going to release it the next few days, including one who could join the big league team this year -- a little bit of an older player."
Washington believes that Martin will be a seventh- or an eighth-inning setup man for future closer Drew Storen. Martin is expected to start the 2010 season with Triple-A Syracuse or Double-A Harrisburg. His fastball is clocked between 92-94 mph.
Martin is coming off a season in which he pitched in 54 games for Saltillo, going 6-3 with a 4.12 ERA. Even more impressive is that he struck out 65 batters in 63 1/3 innings and held opponents to a .244 batting average.
During his three-year career for Saltillo, Martin was 13-6 with a 3.81 ERA and one save.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.