In 2014, Pascoe caught two receptions for three yards and one touchdown while playing for the Falcons.
Niklas was placed on injured reserve after undergoing ankle surgery last season.
Harkey had eight catches for 55 yards and a touchdown last season while McLeod totaled 72 tackles with two interceptions in 16 games.
Smith sustained the injury after taking a brutal hit to the abdomen against the Steelers in Week 16 and had to sit out the team's regular season finale as a result.
Lewis did not receive an extension. This year will be the last year of his contract. The restructuring should reduce his cap number, which is currently $8.2 million.
Supernaw was mostly a reserve in 2014 and had two catches for 27 yards. Trawick is a backup safety that plays on special teams coverage units. Melvin was signed off of the Dolphins' practice squad after injuries decimated the cornerbacks. Jensen was a 2013 draft pick that ended up spending the majority of 2014 on the practice squad.
Gates played 787 snaps in 2014, which ranked 17th at his position and proved far more than many younger tight ends. He was also more productive than nearly all of them with 69 catches for 821 yards and 12 touchdowns, the second-highest total of his career. But while promoting a boxing match in Detroit, he told Monday Morning Quarterback that he would like to scale it back in 2015.
"With injuries and whatnot, I played a little bit more than they expected me to play last season," he said. "I was playing the whole game. How I feel next year, it depends on how much volume they have me doing. I'd like to come in on third-and-7s, red zones, those situations. That's what my contribution is at anyway."
His plan would give young, athletic Ladarius Green a chance to emerge as the primary tight end for the Chargers. Green took a step back last year with just 19 receptions for 226 yards and no scores after racking up 376 yards and three touchdowns in 2013.
McGrath did not play during the 2014 season. In 2013, he caught 26 passes for 302 yards and two touchdowns.
Davis has told the team website that he has placed a great emphasis this offseason on a strength and conditioning program. He had skipped that last year to concentrate on landing a new contract, but has since put aside that distraction.
"I'm here this year because I want to get better," he said. "I want to win. I want to develop some chemistry amongs my teammates and get to know guys. There are a lot of new guys here and you just never know when this game is over for you." He added that he wanted to give football "all I can give it."
Davis caught just 26 passes for a career-low 245 yards last year.