Fielder's solo shot was the only run against Dickey, who scaled back his pitch count in preparation for Opening Day. In four innings, Dickey allowed two other hits and walked no one.
"I felt pretty good about this spring," Dickey said. "I gradually got better and better, and that's the hope."
Dickey on Sunday nearly outdueled Tigers starter Thad Weber, who gave up his only hit on Ike Davis' two-run homer in the fourth. But the Tigers broke the game open two innings later, scoring seven runs against Mets relievers Daniel Herrera and Jon Rauch. After Don Kelly singled home a run off Herrera and Daniel Fields drew a bases-loaded walk against Rauch, James McCann cleared the bases with a two-out grand slam.
The Tigers had borrowed McCann, their top pick in last June's First-Year Player Draft, from Minor League camp to make the 2 1/2-hour drive to Port St. Lucie.
Though Herrera did not help his stock by setting the table for McCann's grand slam, he is all but guaranteed a spot in the Mets' Opening Day bullpen if fellow left-hander Tim Byrdak is not recovered from knee surgery. The only other option for the Mets is rookie Josh Edgin, who has not pitched above Class A ball.
Rauch, who is also guaranteed a bullpen spot, has posted a 7.94 ERA this spring.
Up next: The Mets will use only relievers Monday in a 12:05 p.m. ET game against the Braves at Disney, with Bobby Parnell likely to start. Among a handful of regulars making the trip will be middle infielders Daniel Murphy and Ruben Tejada, who have worked daily this spring to improve their chemistry around the second-base bag.