"We want to congratulate Jordy on an incredible career that included achievements that will result in his eventual induction in the Packers Hall of Fame," said Packers GM Brian Gutekunst. "He is one of the greatest receivers in franchise history and played a vital role in the team's success with not only his play on the field but also for what he provided as a great teammate and leader. We wish the best to Jordy, his wife, Emily, and the rest of their family."
Nelson, who turns 34 on May 31, became a free agent when the Raiders released him on March 14 after just one season with the team.
James Jones, his former Packers teammate, first reported Nelson's decision.
The former second-round pick of the Packers spent the first 10 seasons of his career in Green Bay, where he caught 550 passes for 7,848 yards and 69 touchdowns. He ranks second in Packers franchise history in touchdown receptions, third in receptions and fifth in yards receiving.
He and Aaron Rodgers hold the franchise record for most touchdowns by a receiver-quarterback combination with 65. They broke the record, formerly held by Antonio Freeman and Brett Favre, during the 2016 season.
Nelson's breakout came in 2010, when the Packers won Super Bowl XLV. Nelson caught nine passes for 140 yards and a touchdown in the win over the Steelers. His best seasons came in 2014 and 2016, sandwiched around a lost year in 2015 when he tore his ACL in a preseason game. He caught 98 passes for 1,516 yards and 13 touchdowns in 2014 -- his only Pro Bowl season -- and won the NFL's comeback player of the year award after he put up 97 catches, 1,257 yards and 14 touchdowns in 2016.
The Packers cut him in March 2018 after they couldn't come to an agreement on a pay cut from the $10.25 million he was scheduled to make in the final year of a four-year, $39 million contract. At the time, Gutekunst said Nelson "will always be a member of the Packers family and we look forward to his eventual induction into the Packers Hall of Fame."
During the 2017 season, Nelson's final year in Green Bay, he told ESPN that he believed he had a legitimate chance to get back to a Super Bowl.
"I plan on playing two to four more years, so I think I've got two to four more chances," he said at the time.
Last season in Oakland, he caught 63 passes for 739 yards and three touchdowns. The Raiders released him after they spent big at the wide receiver position by acquiring Antonio Brown in a trade -- and then restructuring his contract to give him more money -- and signing Tyrell Williams to a four-year contract.
Late in the 2018 season, Nelson indicated that he planned to play in 2019.
"It's not always the player's decision, but yeah, that's the plan," he said. "We've enjoyed our time out here so far, enjoyed being with the team and starting the rebuilding process and being a part of that, so yeah, I believe that's the plan."
ESPN's Paul Gutierrez contributed to this report.