It happened in the seventh inning with one out and Marlins runner Ed Lucas on first. Marlins batter Adeiny Hechavarria hit the line drive about knee high right to Ramirez. Instead of catching it, Ramirez knocked it down and tossed it to second to start the double play, but the second base umpire immediately halted the play after the intentional drop.
According to official baseball rules, "A batter is out when an infielder intentionally drops a fair fly ball or line drive, with first [base]...occupied before two are out. The ball is dead and runner or runners shall return to their original base or bases." The rule was correctly applied here, as Hechavarria was ruled out and Lucas had to return to first base.
Ramirez would have been allowed to back off the ball and let it bounce into his glove, but the line drive came at him so fast that he had no chance to do that. In the end, no harm, no foul, and everyone received a good lesson on baseball rules. The Dodgers won the game 4-1.
Video via MLB.