The notion that Welker would one day lead the NFL in receptions, let alone last to the end of the decade, would have been laughable back then. Heck, there were times Welker didn’t look like he was going to make it to the next game.

Instead, Welker is putting up the best numbers of his career. He has improved to the point that he’s no longer the de facto running game of the pass-happy New England Patriots, the guy catching a bunch of short passes to the outside when the defense crowds the box.

Pretty impressive for a 5-foot-9 guy who once looked like he could barely walk after some games.

The story of Welker, who led the Patriots with 122 catches for 1,569 yards and nine touchdowns this season, becoming a great receiver with New England is well known. His combination of great cutting and deep understanding of how quarterback Tom Brady thinks has turned him into one of the top receivers in the league. In four of his five seasons with the Patriots, he has at least 110 catches.

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The lone exception was 2010, when he returned from a torn ACL that occurred at the end of the 2009 season. Welker still caught 86 passes that season.

But this offseason, as Welker hit age 30 and entered the last year of his contract, he spent time in South Florida fine-tuning his skills, working out for up to four and five hours a day while getting a deeper understanding of his body.

“He’s a scientist about how he attacks his training, seeking to be perfect on everything,” said trainer Pete Bommarito, who runs Bommarito Performance Systems in North Miami Beach. “It doesn’t matter if it’s a speed drill or the weight room, he hits it like it’s the last play of the Super Bowl every time. He’s so meticulous about what he does.”

Bommarito’s remarks echo the sentiment of the Patriots’ Bill Belichick, a coach who doesn’t easily dole out praise.

“He practices 100 miles an hour. … He’s very strong for his size and stature but he actually has good playing strength,” Belichick said. “Nutrition, all those things, he’s really borderline fanatical about them. He gets the most out of everything he’s got. I think it’s been hard training, hard work. We all saw how he came back from the injury a couple years ago.”

Stories about Welker’s practice habits have made the rounds.

“I heard about it before I got here, but you don’t really appreciate it until you see it for yourself,” fellow wide receiver Chad Ochocinco said. “Wes is good, man. Really good, and now I see why.”

For defensive back Kyle Arrington, there was a prime example from practice during his rookie season in 2009. At one point, Arrington stepped in front of a pass from Brady intended for Welker, then ran it for a touchdown as part of the practice regimen. Welker chased Arrington all the way to the end zone trying to strip the ball as if it were a live game.

“Wes is intense,” Arrington said with a look that was light-hearted and serious. “Whatever that battery is, Duracell or Eveready, that last so long, he’s that times two.”