On some days, Orrin Thompson probably wishes he could just go back to his old position at defensive tackle, and simply try to blast through the line to either stand up the running back in the hole or pressure the quarterback into an errant throw.

When it's what you've known and done for so long, it seems so much easier.

But there's no going back for Thompson, who is in the third year of a conversion to offensive tackle, no matter how difficult the change can seem at times. And to his credit, Thompson is putting more of those difficulties behind him and starting to show in his second year with the Packers that he has a future at his new position.

Currently holding down the No. 2 left tackle spot for Green Bay, Thompson made significant progress through the offseason program, mini-camps and OTAs with his footwork, hand placement and all the other subtleties that go with offensive line play. His combination of football smarts and athletic ability have certainly helped make the transition, but just as important has been his wholehearted commitment to learning something new, and not living in his past on the other side of the ball.

"When a person makes up their mind to make the switch, that's probably the hardest part to switching over after doing something for so long," Packers offensive line coach James Campen said. "But if they're committed to making the switch and they embrace the position and the opportunity, then good things happen to them, and good things are starting to happen for Orrin."

After playing in 46 games, including 27 starts, at defensive tackle for Duke, Thompson was seen as a better pro prospect on the offensive line at 6-foot-6 and 322 pounds. Undrafted, he signed with Miami after the 2005 NFL Draft and spent that season on the Dolphins' practice squad and the following spring in NFL Europa.

He was released by Miami late in training camp last year and signed to the Packers practice squad on Nov. 15, 2006. At that time, Thompson called himself a "deer in headlights," still learning a new position and then a new offense at the same time.

But of notable benefit since coming to the Packers is that Thompson has been asked to focus on just one position -- tackle, and primarily left tackle. In Miami, that wasn't the case, and it made his transition that much harder.

"I was playing a little of everything," Thompson said. "It was hard to focus on one thing because I was switching everywhere. Anywhere that needed to be filled in, I was doing it.

"Now I get a play and I know at left tackle this is what I do. I don't have to focus as much on the whole play. Eventually I'll get that, but right now it's good to focus (on one spot)."

{sportsad300}Protecting the quarterback's blind side can be a feast-or-famine responsibility, and Thompson has had his ups and downs throughout the offseason workouts. He has lined up across from pass-rush specialist Kabeer Gbaja-Biamila numerous times in practice, and whether he wins or loses the battle, Thompson feels like he's learning with every snap.

Head Coach Mike McCarthy said recently that if the Packers had to play a game right now without starting left tackle Chad Clifton, left guard Daryn Colledge would be shifted over as the primary backup. But with the placement of fourth-round draft pick Allen Barbre at left guard and the recent release of Josh Bourke, the Packers see the potential in Thompson and plan to give him as strong a look as possible.

"I'm hoping to develop a bunch of them," McCarthy said about a backup left tackle. "You never have enough."

Thompson has spent enough time at left tackle to feel more confident entering training camp this year than he has in the past.

His best physical attribute, according to Campen, is what coaches refer to as "length" - not just his overall height but his long arms. With a substantial reach, an offensive lineman can get an initial punch on a rushing defensive lineman before his opponent can engage him. That initial punch from a distance can foil a pass rusher's first move and make him start over with another move, and when it comes to giving a quarterback time to throw, every half-second counts.

"I'm so much more composed now than I was before," Thompson said. "Before I was just trying to get it done, no technique at all. But now the technique is getting there."

Campen concurs, saying Thompson has "improved 100 percent" from the raw player with some basics who arrived in Green Bay last November to the genuine pro prospect he is now.

"Is he good enough to go in there and start playing right now? Probably not, and he'd probably be the first to admit that," Campen said. "But at the same time, he's progressed in a way that we're excited to see him once we get the pads on. We'll see how he's truly progressed. Certainly he has, though. There's no question."

There's also little doubt in Thompson's mind he still has a long ways to go, and as tempting as it may seem to indulge in nostalgia, remembering his days on defense is only helpful to the extent it reminds him he's a different type of player now.

"On defense, it's head-first, get there - it's pretty much a get-after-it mentality," he said. "Offense is, too, but on offense you have to read things, and every step counts.

"It's been a tough road, but I'm getting there."