The 37-year-old right-hander told The Associated Press in his native Dominican Republic that he has spoken with the Rays and Cubs.
"There's a good chance I'll be signing soon, but there still isn't anything firm," Martinez told the AP.
"Chicago and Tampa Bay are the two teams that have shown the most interest and we are negotiating with them, although I've told my agent not to call me until it's a done deal."
Cubs manager Lou Piniella said general manager Jim Hendry hasn't said anything about the team being interested in the right-hander.
"It's never come up, to be honest with you," Piniella said Thursday about possibly signing Martinez. "Since the start of the season, not one name has come up, whether it be pitching or hitting here. Nothing's come up, one way or another."
Martinez, who became a free agent after his four-year contract with the Mets expired following the 2008 season, pitched well in relief in the '09 World Baseball Classic. He has been working out in the Dominican since then and said he wants to play for a pennant contender.
"I need the emotion of competition," Martinez told the AP.
The Cubs did have a scout watch Martinez in the Dominican Republic, but an agreement is unlikely at this time.
Doug Miller is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.