When the Jets added cornerback Hank Poteat to their roster in October, the move hardly seemed worth mentioning. The New England Patriots had just cut him, and the Jets had already signed and then released him once during training camp. Few thought he would provide anything more than some extra depth in the secondary and help on special teams.

Two months later, Poteat has become one of the most important — and overlooked — reasons behind the Jets’ surprising status as playoff contenders. Poteat’s playing time has steadily increased, and since becoming a starter two weeks ago, he has helped the Jets shut down the Houston Texans and Green Bay Packers in their two most lopsided wins of the season.

Poteat played for Jets coach Eric Mangini when Mangini was an assistant in New England, and he showed on Sunday that he clearly understands his role in Mangini’s coverage schemes. Poteat’s best play of the game came in the third quarter, when he lined up across from Green Bay receiver Greg Jennings. The play called for Jennings and the receiver along the opposite sideline, Donald Driver, to run deep routes that crossed in the middle of the field. Offenses run crossing routes in the hopes that the defensive backs will get caught in traffic over the middle, but Poteat saw the play coming, stayed on his side of the field, and broke up Brett Favre’s pass to Driver.

That’s the kind of heads-up play that Mangini hoped to get from Poteat, a player who has continually bounced around from team to team but now appears to have learned something at every stop. The Pittsburgh Steelers drafted Poteat (who played his college ball at the University of Pittsburgh) in the third round of the 2000 draft with the selection immediately before the Jets took Laveranues Coles. Poteat was a kickoff and punt returner and backup defensive back, but he never distinguished himself in Pittsburgh, and the Steelers released him after three years. Poteat had a hard time catching on anywhere else after that, playing just one game for the Tampa Bay Buccaneers in 2003. When he failed to make an NFL regular-season roster in 2004, it could have signaled the end of his NFL career.

But he stayed in shape, and when the Patriots suffered a string of injuries in the secondary during the 2004 season, they signed Poteat to provide some depth for the playoffs. With Mangini as his position coach, he helped New England win the Super Bowl, and he returned to the Patriots last year with Mangini as his defensive coordinator.

This year Mangini brought Poteat in for one August exhibition game before cutting him. His one-day stint with the team at least allowed him to meet his future teammates, and Mangini might have had those teammates in mind when he decided to add Poteat to the roster again in October. The 29-year-old Poteat is the oldest player in the Jets’ youthful secondary, and his experience allows him to give guidance to the team’s younger defensive backs like Justin Miller, Kerry Rhodes, and Eric Coleman.

But this is a secondary reason for Poteat’s presence on the roster. The primary reason is that he’s currently their best option at right cornerback. Left cornerback Andre Dyson is an established starter, but the Jets have struggled to find a consistent player to start across the field from him. Although safety Kerry Rhodes and inside linebacker Jonathan Vilma are good in coverage on short passes to tight ends and running backs, for most of this season the Jets have been chewed up by wide receivers. Poteat is making a difference where the Jets’ other cornerbacks haven’t.

The front office hoped Justin Miller, last year’s second-round draft pick, would emerge as a starting cornerback this season. In two seasons he has never looked comfortable on defense, though, and his contributions come almost exclusively from special teams — he leads the league in kickoff returns

with a 29.0-yard average and two touchdowns. David Barrett showed promise early in the season, with two interceptions in the first three games, but has at times been badly beaten by opposing receivers. Rookie Drew Coleman started three games this year, but he has fallen out of favor since giving up the decisive 57-yard fourth-quarter touchdown pass in the Jets’ 10–0 loss to the Chicago Bears last month. Poteat has less raw talent than Coleman and Barrett — and far less pure athletic ability than Miller — but he won’t make the costly mistakes that novice cornerbacks will.

“It was a situation where we thought we could improve the team,” Mangini said when the Jets added Poteat in October. “I have a lot of familiarity with Hank, and he has a lot of familiarity with the system.” Signing him carried almost no risk — to make room on the roster, the Jets released Derrick Strait, whom they had unsuccessfully tried to trade — and it has had a major reward. Poteat will never be All-Pro, but he’s a smart player, a hard worker, and he plays for a minimum salary. Mangini earned three Super Bowl rings as an assistant on a New England team consistently built around that kind of player. The Jets aren’t there yet, but Poteat is one reason they’re heading in the right direction.

Mr. Smith is a writer for FootballOutsiders.com.