Kalil, who spent the first 12 years of his career with the Carolina Panthers, told Joseph Person of the Charlotte Observer in January 2018 that he was going to retire at the end of the season: "This is going to be the last one for me. ... I'm not doing the farewell tour, that's for sure."
In what was expected to be his final game last December against the New Orleans Saints, Kalil played all 72 offensive snaps in Carolina's 33-14 win.
"A lot of those guys are coming back," Kalil told reporters after the victory. "It was the last time I was ever putting a helmet on. There wasn't a chance I was coming out of the game."
Per Pro Football Focus (h/t Mick Smiley of Cat Scratch Reader), Kalil's overall grade of 63.4 ranked 16th among all centers in 2018.
The Jets needed help on the offensive line, with Pro Football Focus rating their current group as the fifth-worst in the NFL heading into this season.
Quarterback Sam Darnold's development is the most important storyline for the Jets in 2019. Anything they can do to give him additional protection behind the line of scrimmage should be done.
Kalil, 34, is a five-time Pro Bowler and started all 16 games last season for the first time since 2014.