Alvarez went 12-7 with a 2.65 ERA for Miami last season. The right-hander, who turns 25 on April 18, was the favorite because Jose Fernandez is recovering from Tommy John surgery. Alvarez pitched a no-hitter against Detroit on the final day of the 2013 season.
Marlins manager Mike Redmond called the decision a ''no brainer.''
''This guy had an unbelievable year last year,'' Redmond said Sunday. ''He stepped up at a time last year when we really needed somebody to step up, when Jose went down. I think he really turned the corner as far as being a starter and knowing and proving to himself and a lot of people that he can win big league games and go out there and pitch deep into games as well.''