Miami now is carrying 13 pitchers and just 12 position players, meaning manager Mike Redmond will be working with a short bench for at least a couple of games.
"We needed a guy who can pitch multiple innings," Redmond said. "We've had to use all those guys the first two games of the series, which we weren't anticipating."
The bullpen has been called into service because Miami's starters worked a total of 6 2/3 innings in the first two games of the series with the Giants at Marlins Park. On Friday, Nathan Eovaldi was lifted after four-plus innings, because he was tagged for eight runs.
Henderson Alvarez on Saturday was lifted after 2 2/3 innings due to a left shin injury. Alvarez was struck just above the ankle by a comeback shot off the bat of Joe Panik in the third inning.
Sam Dyson, the primary long reliever on the squad, threw 70 pitches in 3 1/3 innings. He won't be available for a few games.
Lucas, who had been seeing starting time at second base, became the choice to send down to New Orleans. Jordany Valdespin was called up Saturday, and he has made two straight starts at second.
"It's not perfect. It's not ideal," Redmond said. "Obviously, we lose a position player, so we're going to play short a position player, which is not a perfect scenario. But we need the pitching."
DeSclafani made five starts in the first half for Miami, posting a 1-2 record and a 7.40 ERA.
"We know he has quality stuff. He knows that," Redmond said. "When he gets in there, we need him to throw strikes and eat up innings."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter