The Jets likely will carry only three in the regular season. They tried to trade Petty during the draft, but they found no takers.
Petty, a fourth-round choice in 2015, posted a 1-6 record as a starter over the past two seasons. All told, he had 4 touchdown passes and 10 interceptions and completed just 53 percent of his attempts.
He was pressed into duty last season when McCown suffered a season-ending hand injury in the 13th game. Petty struggled in the final three games, as the Jets scored only 32 points and lost all three.
In 2016, Petty replaced Ryan Fitzpatrick when the team was mathematically eliminated from the playoff race. Petty won his first start, but he lost the last three.
The former Baylor star sat on the bench for a year with the Jets as he made the transition to a pro-style offense from a college spread system. His progress also was slowed by injuries, including a torn labrum in his non-throwing shoulder in the 2016 finale.