Young was informed by general manager Sandy Alderson and manager Terry Collins after the Mets' 5-4 win against the Philadelphia Phillies on Friday night. He hit .205 with eight homers and 28 RBIs in 254 at-bats.
Young expressed surprise at being dropped so close to Sept. 1, when rosters will expand.
"It caught me a little bit off-guard," Young said. "I wasn't expecting it. I understood that the playing time had changed. And I realized that. But I didn't think this was coming. The team has to do whatever they feel is best for the team. I respect that."
Added Alderson: "At some point you have to move on. I think this was about the time that we needed to do that. Chris has been, I think, an outstanding teammate to the other guys on the team. I've liked Chris a lot since the first time I met him. Unfortunately, it didn't work out completely as he would have liked, as we would have liked. And, at some point, it's time move on to something else."
Young, 30, had signed a one-year, $7.25 million deal with the Mets on Nov. 26 despite struggling with the Oakland Athletics in 2013.
"We were looking for a bounce-back," Alderson said. "Some of the material that we looked at suggested that was a possibility. We knew we were taking a little bit of a risk, but it was a one-year deal, so we were willing to do that. At the time we were looking for some protection in center field."
Added Young: "You come in with really good intentions and the team has really good intentions. And sometimes it just doesn't go as planned. I'm comfortable with the fact that I worked hard and I truly did my best. It's just unfortunate that didn't work out as planned. I'm grateful for the opportunity. One door closes and another one opens hopefully."
Matt den Dekker, whose .334 average leads the Pacific Coast League, was pulled from Triple-A Las Vegas' game against Albuquerque in the first inning on Friday night and informed of his promotion.
Collins said den Dekker should get regular playing time in left field, so the Mets can evaluate whether he can contribute at the major league level. Kirk Nieuwenhuis, another young player due for more playing time, will rotate among outfield spots and otherwise serve as a pinch hitter.
With den Dekker and Nieuwenhuis both lefty batters, Eric Young Jr. should start a fair amount against left-handed pitching.
Alderson said one motivation for dropping Chris Young was to ensure a lefty bat was on the bench, which had been an issue since Bobby Abreu was designated for assignment earlier in the week.
"We know that Kirk can come off the bench, and has done a nice job for us in a number of positions," Alderson said. "Matt probably needs to play a little bit so that we can see really what he can do and what we have."
Alderson said the Mets losing two of three games at first-place Washington midweek, which dropped the club nine games off the division lead, was not a factor in turning toward youth. The GM suggested that the Mets were not compromising 2014 competitiveness by starting to audition younger players.