New York had been down to one healthy quarterback on the roster. Sam Darnold is out with mononucleosis, and Trevor Siemian is done for the season with an ankle injury.
Fales will provide insurance behind Falk when the Jets face the New England Patriots in a massive road test Sunday at Gillette Stadium in Foxborough, Massachusetts.
The 28-year-old Fales has experience in Jets head coach Adam Gase's system. Fales was a member of the Chicago Bears in 2015, when Gase was the offensive coordinator, and he was on the Miami Dolphins roster from 2017-18 while Gase was head coach.
Fales hasn't played much in the regular season, though, with just three appearances to his credit.
His most extensive playing time came in 2017. Fales appeared in two games, going 29-of-43 for 265 yards with one touchdown and one interception. He also rushed for a score.
During the 2019 preseason, Fales played in three games for the Detroit Lions. He completed just 48.8 percent of his passes for 310 yards with one touchdown and one pick.
Given how overmatched the 0-2 Jets look entering their matchup against the 2-0 Patriots, it isn't outside the realm of possibility that Fales will see some action. Falk, a 2018 sixth-round draft pick of the Tennessee Titans, saw the first regular-season playing time of his career Monday in New York's 23-3 loss to the Cleveland Browns at MetLife Stadium.
While the Jets didn't do much offensively, Falk did manage to go 20-of-25 for 198 yards with no touchdowns or interceptions.
On Sunday, Falk and the Jets will face a Patriots defense that has allowed an NFL-low three points through two games.