Only six years into his NFL career, Robertson has gone through several coordinators, coaches and defensive systems, and the defensive tackle even has switched teams thanks to the offseason deal that landed him in Denver.

But the difficulty of his most recent conversion was unexpected, even for someone who has learned how to adapt.

What accompanied his move to the Broncos was supposed to be old hat.

There would be no more nose tackle in the 3-4 alignment, where, playing at about 320 pounds, he felt sluggish and his responsibilities protecting two gaps in the middle of the line were the antithesis of his attacking sensibilities.

Robertson had made it work in that spot for two seasons with the New York Jets . But then he was sent packing April 28 so the Jets could find someone even bigger and a more natural fit on the nose, Kris Jenkins.

The Broncos, who got Robertson for a bargain-basement price, plugged him right into the heart of their one-gap scheme up front.

It would put him back into attack mode.

Yet, the moves that once felt so natural to Robertson, first as a dominant player at the University of Kentucky, then as he morphed into his early pro career, now felt strangely foreign.

Progress is being made

So it has taken the 27-year-old some time to rediscover his comfort level, but his progress has spiked upward in the past month.

"I thought it was going to be better. I'm talking about my play," said Robertson, who Sunday returns to the Meadowlands for the first time since his exit from the Jets (2:15 p.m. MST, CBS 4). "My play so far has not lived up to my standards, (though) I feel like I'm getting my 'swag' now the last few weeks."

It all boils down to technique.

In the 3-4, the nose tackle is aligned straight over the center. When his offensive counterpart darts one direction, he reads his move and acts accordingly.

In his new-old responsibilities, quickness at the snap and attacking the assigned gap are paramount.

"He had to get back to that, of really striking," said Bill Johnson, one of two Broncos defensive line coaches.

Robertson's slow start might be tied to the caution taken with his left knee, which has been worn down to a nearly bone-on-bone condition since a college injury.

When Robertson arrived in Denver , the Broncos , wanting to ensure he could last the long haul, eased him into workouts.

Also recovering from wrist surgery, Robertson participated sparingly in minicamps and preseason games. And when the regular season began, he was somewhat rusty, especially in terms of playing his proper stance and with timing.

"And you have to be technically sound," Johnson said. "It's like a golfer, a hitter in baseball, a free-throw shooter. There's some technique to it. And he's gotten better as the year's gone on."

Since the bye week, Robertson has played with "a much stronger base," Johnson said. "He's become a much stronger player."

His presence is felt

While playing exclusively on first and second downs as part of the Broncos' eight-man, game-day rotation along the front four, Robertson has brought a quiet, lunch-pail presence.

"He's kind of showed me the ropes," said fellow defensive tackle Marcus Thomas, who pairs with Robertson extensively in the base defense. "And he's one of those guys in the film room, he knows what's going on. He's a real student of the game, and he's helped me with that."

The situational role has served not only to keep Robertson fresh but produced other big-picture consequences. The Jets will receive nothing in terms of draft-pick compensation for Robertson if he plays less than 65 percent of the snaps this season. He is playing considerably less and isn't expected to approach that threshold by season's end.

The one game Robertson missed was because of a knee problem, though not for his chronic condition.

"I've been all right," he said when asked how he has held up. "The issue that everybody makes a big deal about really hasn't bothered me at all. I've had other nicks and knacks, but healthwise I'm good. I feel like I'm getting stronger."

What Robertson isn't getting is emotional about his Jets reunion.

"Not at all, man - another game," he said.

Winds of change

The Jets moved up in the 2003 draft to pick Robertson fourth overall, and he would play three seasons for Herm Edwards. But Eric Mangini took over as coach in 2006, and things changed.

Robertson suspected after the 2007 season his days in New York were numbered, especially considering he was due a $3 million bonus in June.

"I kind of got the feeling something was about to happen - either something really good or really bad," said Robertson, whose deal has been reworked through 2013 by the Broncos.

Now, Robertson describes his experience with the Jets as mostly positive. He finished with 319 tackles (188 solo) and 14 1/2 sacks in his five seasons there.

"New York was cool. I have no beef with New York," he said.

His adjustment to Denver, the locale, has been easier than the one on the field.

"Football's Football, no matter where you're at - city, whatever," he said. "I've just tried to come in here and do what I'm asked to do."

Robertson is playing at his preferred weight of about 308 pounds. And, though his statistics don't jump off the page - he has made 30 tackles to date - Johnson is seeing "hidden production," such as Robertson disrupting blocking schemes and playing strong on his blocks.

Twenty of Robertson's tackles have come in the past five games.

"The simple matter of the story is it's a guy who's getting a feel for where we're at and what're doing," Johnson said. "And he's starting to contribute a little better in his role and for what he's doing."

ETC.: The Broncos waived safety Roderick Rogers on Tuesday, clearing the roster spot needed to sign veteran fullback Andrew Pinnock. As of the close of the business day at the NFL office in New York, the Broncos had not reported Pinnock's signing, but he was scheduled to receive a physical to check his surgically repaired knee. It was the second physical the Broncos had given Pinnock in recent weeks; they also worked him out earlier this month. He underwent microfracture surgery in February and was released by San Diego at the end of training camp. Rogers made his first career start in Sunday's 31-10 loss to the Raiders. . . . The Broncos reported no formal workouts to the league Tuesday.