Rivera was outrighted to Triple-A New Orleans on Tuesday, Andre Fernandez of The Athletic reports. The utility man hit just .173/.269/.216 across 111 games (160 plate appearances) with the Marlins in 2018.
Rivera entered Sunday's win over the Nats in the seventh inning as a pinch hitter, going 1-for-1 with a run scored and a stolen base. The 26-year-old is back to coming off the bench now that Martin Prado has rejoined the lineup, and Rivera's .202/.316/.253 slash line on the season may keep him there even if injuries open up playing time around the Marlins' infield again. He currently qualifies at second base, third base and shortstop in most leagues and could add first base and outfield to his portfolio in the second half, but even in deep NL-only leagues, there's little reason to carry him on a fantasy roster.
Rivera went 1-for-3 with two walks in Sunday's win over the Reds, but he also committed his first two errors of the season. The 26-year-old has seen little action this season behind Miguel Rojas at shortstop, and Rivera's anemic .148/.258/.148 slash line in 31 plate appearances and unreliable defense aren't doing anything to change that. Expect him to be replaced on the roster by JT Riddle as soon as the Marlins are confident Riddle is fully recovered from his shoulder injury.
The Marlins selected Rivera's contract from Triple-A New Orleans on Thursday, Clark Spencer of the Miami Herald reports. Rivera slashed .304/.373/.457 through 51 plate appearances this spring, but the short sample was enough for the non-roster invitee to catch on with the big club as a reserve infielder. The 25-year-old will provide organizational depth on a team that is currently down two infielders in J.T. Riddle (shoulder) and Martin Prado (knee). To make room on the 40-man roster, Austin Nola was designated for assignment, and Brett Graves was moved to the 60-day disabled list.
Rivera signed a minor-league contract with an invitation to spring training with the Marlins on Friday, Joe Frisaro of MLB.com reports. Rivera only played in one major-league game with the Brewers this past season, and spent a majority of his time with Triple-A Colorado Springs. He slashed .218/.282/.314 with the Sky Sox during 107 games, and will likely serve as organizational infield depth for the Marlins while playing in Triple-A once again in 2018.