Mason, 37, is the Ravens' all-time leader in receptions and receiving yards. The Ravens released him prior to camp to create $4.5 million in salary-cap room.
"After a lot of very thoughtful and careful consideration, conversations with my family and prayer, I have decided to sign with the New York Jets," Mason said in a statement. "I'm looking forward to working under Rex [Ryan] and rejoining some familiar faces."
The Ravens have lost out on two wide receivers — Malcom Floyd and Mason — in a span of 24 hours. A league source denied a report in The San Diego Union-Tribune that Floyd accepted less than the Ravens offered to stay with theChargers.
Now, the Ravens may turn to former Jets receiver Jerricho Cotchery.
But Cotchery is visiting the Ravens' most heated rival, the Pittsburgh Steelers, on Sunday, according to a league source. The Ravens are one of four teams who are seriously interested in him, the source added.
Cotchery, 29, had 41 catches for 433 yards and two touchdowns for the Jets last season. He has expressed interest in the Ravens, a league source said.
From 2006 to 2008, Cotchery had at least 70 catches.
Ravens players were not sure what Mason planned to do when they spoke with reporters after the team's practice at M&T Bank Stadium on Saturday. Quarterback Joe Flacco said that he hadn't spoken to Mason since he was released. He put his support behind Mason, but not before delivering a playful shot.
"Derrick is a great locker room guy," Flacco said before cracking a smile. "He can be a little bit of a diva sometimes, but that's all good and fun with him for the most part.
"Derrick is a great wide receiver. He can help this team out in my opinion. Yeah, I would welcome him back immediately.".
Wide receiver Anquan Boldin said he spoke with Mason a couple of days ago.
"Me and Derrick have a great rapport," Boldin said. "I think he can help us out tremendously. I would love to have him."
"When we were heading into the offseason, we were a pretty veteran team. That was one of those things that we could feel pretty confidently about going into the lockout," Flacco said. "Now, we got young pretty quickly. So, any time you get a guy who is a veteran and has played games in the NFL, it can help your locker room."
J. Smith's makes brief appearance
The club's 27th overall pick in April, Smith participated in the first hour of practice at M&T Bank Stadium. But shortly afterward, he donned a white hat and watched from the sideline.
In the locker room, Smith said his abbreviated appearance was scripted by the coaching and medical staffs.
"It was never the plan to go full today," he said. "It was to just go out there and run around and loosen up. I felt good, but they want to wait until next week for me to get back and give it a full-go."