As the Jets attempt to solve the puzzle that is their struggling running game, one thing is clear — rookie center Nick Mangold is part of the solution, not the problem.

Mangold, a first-round pick (29th overall) out of Ohio State, was forced into the starting lineup during training camp when veteran Trey Teague suffered a broken left ankle in June.

The last time a Jets rookie was forced to replace a starter during camp was 2003, when Dewayne Robertson took over for veteran Josh Evans, who was suspended four games for substance abuse. Robertson, like Mangold, took his lumps.

Mangold, however, is giving as much as he is receiving, despite playing one of the most demanding positions on the field. He must make all the line calls and battle cagey veterans in the NFL trenches.

“Right now, I’m having a lot of fun trying to learn everything I can,” Mangold said yesterday. “The mental part is the toughest. It’s a big playbook. There’s a lot going on. Teams do a lot of different stuff.”

Mangold, however, has been undaunted.

In last week’s 28-20 victory in Buffalo, he made a key block on a quarterback sneak by Chad Pennington on a fourth-and-one from the Bills’ 33 with 6:12 left to play. Pennington gained 4 yards on the play in what proved to be the game-winning drive.

Also, Mangold made big blocks on two short-yardage touchdown runs and helped limit the Bills to one sack. The Bills notched seven sacks the previous week against the Dolphins.

“Nick has done a nice job for us,” said left guard Pete Kendall, who is expected to start against the Colts (3-0) on Sunday after missing two games with a hamstring injury.

“The most impressive thing in dealing with Nick is that the X’s and O’s haven’t overwhelmed him. In the running and passing games, he gets us set and identifies our assignments. He has been pretty solid with all the stuff … people thought a rookie center might struggle with.”

Said right guard Brandon Moore: “We’ve had some looks where he’s had to make adjustment calls on his own and he got us straight at the line of scrimmage.”

Mangold has played so well that coach Eric Mangini rarely mentions his name in meetings. Kendall said he can’t recall a time when Mangold was admonished in a meeting for making the wrong line call.