At the start of the season, the biggest question for the Jets was whether quarterback Chad Pennington was healthy enough to be productive. While his strong performance thus far has provided a definitive answer, everything else about the team seems to be in doubt.

The Jets’ defense has struggled, appearing to be equally porous against the run and the pass. Penalties have killed the team. The running game has disappeared, a development that can be attributed mostly to a failure to plan for life after Curtis Martin. Despite this array of problems, the team finds itself tied for first place in the AFC East heading into the final weekend of September.

Any optimism about the standings is likely to be tempered this weekend as Gang Green plays host to the Indianapolis Colts. Peyton Manning leads a high-powered offense that ranks second in points per game and will give the Jets their biggest challenge yet.

INDIANAPOLIS COLTS (3-0) AT JETS (2-1)
(Sunday, 1 p.m., CBS)

WHEN THE JETS HAVE THE BALL What’s most remarkable about the Jets 2-1 start is that they’ve been able to win despite the complete absence of a running game: They rank dead last with a 2.6 yards per carry average. Last week, the Jets activated second year back Cedric Houston and deactivated Derrick Blaylock, who had started the first two games. Houston carried the ball only twice, and starter Kevan Barlow plodded for 31 yards on 12 carries.

Late in the game, however, the answer to their running woes may have emerged. Rookie Leon Washington zigged and zagged, eluding tacklers and making some big gains. His display should earn him a chance at more playing time.

The Colts are quick up front, but they use that speed to pressure the quarterback.Their aggressive moves in that direction can leave them vulnerable against the run. In fact, they rank 28th in the NFL in rushing yards allowed per game. Defensive end Dwight Freeney had 11 sacks last year but has been shut out so far this season.The vaunted Indianapolis pass rush has recorded just five sacks in three games this season.

Injuries in the Colts secondary are also a cause for concern. Hard-hitting safety Bob Sanders missed last week’s game with a knee injury and is listed as questionable on the Colts injury report. Four cornerbacks, including starter Nick Harper, are also listed as questionable.

WHEN THE COLTS HAVE THE BALL The Colts are averaging 30 points a game, thanks largely to a passing offense that ranks second in yards per game. When he’s given time to throw, Manning can pick apart any defense. So far, the offensive line has been successful, surrendering just five sacks on 115 pass plays.

In past seasons, opposing defenses focused on stopping the Colts passing game, using zone coverage to contain the receivers. This year, head coach Tony Dungy says defenses have been more geared to stopping the run, which has opened passing lanes for Manning and his receivers. Marvin Harrison and Reggie Wayne have combined for 36 catches and 618 yards. If they continue to receive so much single coverage, they’re both going to end up with 100 catches.

The reason for this shift has been the addition of rookie running back Joe Addai. While the early numbers haven’t been remarkable, the combination of Addai and veteran Dominic Rhodes is proving to be effective. Both have a nice combination of size and speed, and both are effective receivers out of the backfield.

This ought to worry the Jets, whose run defense has gotten progressively worse each week.

The catch-22, of course, is that if defensive coordinator Bob Sutton brings up linebackers or safeties to help stop the ground attack, he has to leave those receivers in man-to-man coverage. Nobody’s better than Manning at spotting those match ups, changing the play at the line of scrimmage, and exploiting mismatches.

KEYS TO THE GAME First, the Jets need to score early. They have been held scoreless in the first quarter of every game this season. Gang Green can’t afford to dig themselves into a hole against an offense as powerful as this one.

Second, the Jets need to continue to force turnovers. Last week, they managed a win because they forced three turnovers and kept the Bills from converting long drives into points.

Lahman’s Pick: Colts 28, Jets 17