Tate signed with the Lions in free agency before the 2014 season -- the first big-splash signing of the Jim Caldwell era -- and immediately became the team's most consistent receiver. He had 90 receptions in each of his four full seasons with the Lions and was a 1,000-yard receiver in three of those years. This year, Tate is on pace for reaching both of those markers again, with 44 catches and 517 yards with 3 touchdowns.
Tate, 30, is also one of the best yards-after-catch receivers in the league with 285 yards -- No. 13 in the league, but No. 3 among receivers.
Howie Roseman, the Eagles' vice president of football operations, said the focus is on winning now, which is why a 4-4 team was willing to trade a third-round pick for a pending free agent.
"We think we have a really good football team and we are adding a really good player. ... We are going to keep our foot on the gas and that's our message," Roseman told reporters. "That's our message to our fans and that's our message to our organization. We are not going to sit on our hands.
"When you get an opportunity -- it's hard to find really good players and this is a really good player, who really fits this culture, this community and this city. He's a hard-working, determined guy with a lot of passion and a lot of energy. What he does with the ball in his hands is special."
Eagles quarterback Carson Wentz and Tate tweeted their excitement about the trade.
Tate is in the final year of the five-year contract he signed with the Lions, and by dealing him for a third-round pick, Detroit essentially gets back the likely compensatory pick it would have netted had he left in free agency after the season.
The defending champion Eagles are in second place, behind the Redskins, in the NFC East. Philadelphia has been looking for a receiver to complement Alshon Jeffery since Mike Wallace went down with a broken leg in Week 2.
"We know this is an incredibly smart guy and an incredibly hard worker," Roseman said of Tate. "We feel very confident that a lot of things we are doing here are things that he's done in the past. The bye week certainly helps. This isn't a situation where we're getting a guy on Tuesday and he's got to come in and play on Sunday. We have a little bit of time to get him up to speed. During the season, the playbook gets a little smaller because it's game-plan-specific, so I think that will help him, too."
Lions general manager Bob Quinn issued a statement about Tate.
"On behalf of our entire organization, I would like to sincerely thank Golden for his countless contributions to our team during his time as a Detroit Lion," he said. "For more than four years Golden displayed an unwavering commitment to not only his coaches and teammates, but also the City of Detroit. The impact he made on and off the field set an example for our team and serves as a testament to his character. We wish Golden and his family the very best in the next step of his career."
Tate also thanked Detroit.
Before this trade, the Lions (3-4) appeared to be in acquisition mode when they acquired defensive tackle Damon Harrison from the Giants last Wednesday. Also Tuesday, Detroit restructured the contract of wide receiver Marvin Jones, saving $2.2 million against its salary cap, sources told ESPN's Michael Rothstein.
ESPN's Michael Rothstein and Tim McManus contributed to this report.