Miami signed the 31-year-old Marmol to a $1.25 million, one-year deal this month on the heels of a strong showing by the right-handed reliever in the Caribbean Series in Venezuela.
In that series, he was strong out of the bullpen for the Dominican Republic. He worked two perfect innings, striking out a pair and not issuing a walk, and was clocked in the mid-90s.
Miami manager Mike Redmond said the organization's scouting staff had also watched Marmol in the winter league and was impressed.
''We've had scouts watching him all winter, and all the reports on him were great. Hopefully, he can build off what he's done in the winter,'' he said.
A change in mechanics may have been the difference for Marmol, who had a 5.86 ERA in 31 games with the Cubs last season before finding some success with the Dodgers.
''He looks like he's changed his delivery a little bit. I remember him over the past being a little bit more across his body,'' said Redmond, a former catcher. ''Now he's kind of squared up and centered up his front foot on his delivery.''
Trouble throwing strikes was Marmol's problem with Chicago, where he played for the better part of eight seasons. But he has 730 strikeouts in 504 career games.
Giving him a chance has little risk for the Marlins, as Redmond sees it.
''He's got a great slider and a good fastball,'' Redmond said. ''Like all those guys, it's about pounding the strike zone and getting ahead of the hitters. It makes your breaking ball so much more effective.''
Marlins newcomer Casey McGehee played with Marmol in the minors for three seasons in the Cubs' organization and he faced Marmol when they were in the NL Central with Milwaukee and Pittsburgh.
''There's not a right-hander in the league who wants to face him (when he's on). He has a tremendous slider and his fastball has good movement on it. Sometimes with guys like that their stuff moves so much it's hard to rein it in,'' McGehee said. ''He's got such good stuff that he doesn't even have to throw it over the plate. Just start it over the plate. With some guys it's just, 'Hey, just go throw.'
''He's such a good guy,'' McGehee added. ''Even when I was across the field from him, he was someone I'd pull for.''