"At this stage in my career, there wasn't many opportunities for me," he said. "They gave me an opportunity and I jumped on it, and I'm just here to help out any way I can.
"I don't have anything to prove to anybody. I think my career speaks for itself."
At times Saturday, Johnson was with the second team and got chances ahead of both Justin Hunter and Dorial Green-Beckham. Johnson made a pretty catch going out of bounds on the right sideline on a Marcus Mariota rollout to the quarterback's right. Johnson also made another nice grab when a well-thrown pass from Matt Cassel fell over the receiver's shoulder up the left sideline, leaving Johnson to beat cornerback Cody Riggs with ease.
"I was just out there making plays, enjoying the moment," Johnson said. "I'm just trying to get better as a player."
The Titans spoke glowingly about adding a player who ranks eighth in the NFL in career receptions (1,053) and ninth in yardage (14,100).
"He made some really eye-popping catches," safety Rashad Johnson said. "He knows the game. He's going to be a great addition to this team. I think it was a huge, huge pickup for us. He's only going to make us much more explosive offensively and help open up that run game."
Johnson, 35, will put pressure on Hunter, who is in a contract year, and Green-Beckham, who hasn't established himself heading into his second season.
"Just to see him at the age he is and at the point in his career and see him learn some of the playbook so fast and go out and execute and make the plays he made, I think it's really exciting," receiver Kendall Wright said. "He can make the group really competitive, and that's what we need."