DENVER -- New York Mets first baseman Lucas Duda landed on the disabled list on Saturday, a day after he was forced to depart a game against the Colorado Rockies in the seventh inning when his back locked up.

Duda will get a second opinion on Monday with doctor Robert Watkins in California. That is the doctor who treated David Wright for his lumbar stenosis.

Left-handed reliever Dario Alvarez took Duda's roster spot. The Mets intended to promote Alvarez anyway, so Duda landing on the DL saved a demotion for rookie outfielder Michael Conforto.

Duda had missed six starts with a strain in his lower back before returning to the lineup Tuesday in Baltimore.

"He obviously never fully healed to have it reoccur that quickly," assistant general manager John Ricco said. "We gave it a chance last time [without the DL]. The four, five, six days didn't knock it out. I think it's obvious we need to give it more time. While he was cleared to play last time, obviously there was still something in there that it reoccurred. So we decided this time to give it the full 15 days."

"It just kind of came back," Duda said before Saturday's game.

Duda is hitting .246 with 21 homers and 56 RBIs in 405 at-bats this season. Daniel Murphy, Michael Cuddyer and Kelly Johnson likely will share first-base duties in Duda's absence.

Alvarez, 26, made four appearances for the Mets in 2014. He had a 1.08 ERA in 10 relief appearances this season with Las Vegas after a late-July promotion from Double-A Binghamton. Lefties were 2-for-14 against him with Vegas. Batters from that side of the plate hit a combined .118 (8-for-68) against him between the two levels.