Young, who was in the starting lineup against the Twins on Monday at Comerica Park, batting third and playing left field, was replaced on the 25-man roster by outfielder Rene Tosoni, who was recalled from Triple-A Rochester.
"We appreciate everything Delmon has brought to this ballclub over the last few years," Twins general manager Bill Smith said. "He's grown up with this club and become close to a number of players on this club. He was a good teammate and he came over here as a young player, so it was a difficult thing to make this deal. But at this time, we had to look ahead and turn the page."
Young, 25, batted .266, with 16 doubles, four home runs and 32 RBIs in 84 games this season as a member of the Twins. He missed 19 games with a strained left oblique suffered in April, and 16 games with a right ankle sprain suffered in late June.
He was placed on waivers last week, and the Tigers claimed him, meaning the Twins had until 1:30 p.m. ET on Monday to work out a deal with Detroit or pull him back off waivers.
The move, however, still came as a surprise according to many in the Twins' clubhouse, especially considering the fact he simply changed clubhouses at Comerica Park.
"It's just the way it happens in baseball," Twins manager Ron Gardenhire said. "We've got a lot of outfielders and can use a couple different people, and now we can get two players back for him. It's sad to see Delmon go. We liked him an awful lot. He's been a lot of fun for us."
Young actually found out about the trade on the bus ride over to the ballpark, and exchanged his goodbyes before heading to the Tigers clubhouse.
"I don't know if it's hit me yet," said catcher Joe Mauer, who arrived early and wasn't on the bus ride. "I have been out there to see him yet. I like Delmon as a person and a teammate. But I don't think it's really hit me yet."
Young also became the second member of his family to play in Detroit, as his brother Dmitri spent five seasons with the Tigers from 2002-06.
"My brother had a great time when he played out here, especially with the team that they have, it's a great opportunity to play out here," Young said. "Everyone was looking confused when I walked in the clubhouse. I don't think anyone knew what happened."
Young, who can file for salary arbitration after the season, is making $5.375 million this year, and given his decrease in production, likely would've been a non-tender candidate if the Twins decided not to trade him.
Young was originally acquired by the Twins prior to the 2008 season in a trade that sent right-hander Matt Garza to Tampa Bay. In in 497 games with the Twins, Young hit .287, with a .324 on-base percentage, .429 slugging percentage, 47 home runs and 273 RBIs.
He had a breakout season last year, hitting .298 with 21 homers, 46 doubles and 112 RBIs, but failed to build on his success this season.
"He had a great year for us last year," Gardenhire said. "He's had a couple different bouts with an ankle injury, a rib injury and a foot injury in Spring Training. All those things come into play. As Delmon would tell you, he's always been a slow starter. It's just carried over a little bit."
The left fielder has also had his problems defensively, as advanced metrics such as Ultimate Zone Rating (UZR) have rated his range as below average throughout his career.
The Twins will now turn to rookie Ben Revere to man left field in Young's absence, as he'll bring his speed and athleticism to the club down the stretch.
"Revere has been an exciting player for us this year," Smith said. "We'll see how it plays. This is the time to make this deal and move forward, and get a chance to see Ben Revere now."
Nelson, meanwhile, was selected by the Tigers in the 10th round of the 2010 First-Year Player Draft and made 26 appearances, including 17 starts, for Class A Lakeland this year. He's a local product, as he attended Edina (Minn.) High School.
The 6-foot-7, 233-pounder posted a 4.87 ERA with 50 walks and 87 strikeouts in 105 1/3 innings pitched. He has been assigned to Class A Fort Myers.
"He's a big-bodied left-handed pitcher. His numbers in the Florida State League this year aren't too overwhelming, but we got some good reports on him. ... He's probably had more success as a reliever but we're going to let him come over and make his own impression. He has enough pitches to be a starter."
The Twins will also receive a player to be named on or before Oct. 15, but Smith said he expects the move to be announced before then.