NFL

WELK-OME ADDITION

SCOTTSDALE, Ariz. – On March 5, when a certain transaction was officially announced, more than a few eyebrows were raised around the NFL.

The Dolphins’ trade that day of Wes Welker to the Patriots for a second-round and seventh-round draft pick left many scratching their heads.

“I was shocked, but I was ecstatic that we got him – so, so ecstatic,” Patriots safety Rodney Harrison said.

“We got him and we said, ‘How did that happen?’ ” Patriots linebacker Tedy Bruschi said. “To get a player like that . . . for a team to give someone up like that . . .

“I don’t think he’d had a statistical year like he’s had this year or even close to it in his past seasons, but we always considered him a threat and a guy that we had to focus on first and foremost when it came to the Miami Dolphins’ passing offense.”

One AFC general manager echoed the thoughts of the Patriots players and said his executive colleagues around the league felt the same way: How could this happen?

“I think if the Dolphins had it to do all over again, I’m sure they would,” the executive told The Post last night. “I was definitely a little bit surprised to see him traded. He was a good punt returner and he gave people problems in the slot.

“I guess the Dolphins were trying to get the most they could get for him, trying to salvage whatever they could out of the situation.”

Welker entered this season having caught 96 passes for 1,121 yards and two touchdowns in his previous two seasons with the Dolphins.

This year as a Patriot, he caught a franchise-record 112 passes for 1,175 yards and eight TDs. In the Patriots’ two playoff games, he made 16 more catches for 110 yards and two TDs.

Not bad for a 5-foot-9, 185-pound receiver who was an undrafted free agent out of Texas Tech, the only Division I school to offer him a scholarship.

“I believe he is, pound for pound, the toughest ball player in the league,” Patriots linebacker Junior Seau said. “That little termite is so shifty, agile and strong. You knew Wes had it – he just needed someone to believe in him.”

The Patriots believe – and yet they can’t believe.

They believe in Welker’s ability and yet they cannot believe the Dolphins ever let him go.

“We played him twice a year and couldn’t handle him,” Bill Belichick recalled of Welker’s days in Miami. “He killed us every time we played against him. We couldn’t cover him one-on-one. We couldn’t tackle him, couldn’t cover him and had to double him a lot. He was a tough guy for us to match up with.”

Now Welker is everyone else’s problem.

Belichick recalled a game on Oct. 10, 2004, when Welker, who was already catching passes and returning punts and kickoffs, was pressed into duty as a kicker when the Dolphins’ Olindo Mare was hurt in pregame warm-ups. Welker kicked a 29-yard field goal and a PAT in the game against the Patriots.

“That he was able to go out there and kick in that game speaks to the kind of player he is,” Belichick said.

As a receiver, Welker is, quite simply, an impossible match-up for teams trying to cover him in the slot. He carves up opposing defenses in the middle of the field and allows Randy Moss to run free down the field.

The Giants are going to have to make a choice in Super Bowl XLII on Sunday. They either can double cover Welker or, like the Jaguars and Chargers did in the previous two playoff games, double Moss and hold their collective breath with Welker.

“When the game is on the line, that’s who I’m throwing to,” Tom Brady said. “Wes is fearless going over the middle. I don’t remember any matchups where he didn’t have the edge because of his quickness.”

Bruschi said Welker’s “savvy” helps him own the middle of the field.

Linebacker Larry Izzo marveled at Welker’s “courage and heart.”

That courage and heart and all of the intangible things Welker brings to the Patriots are why no one can figure out how any team would trade him away.

mark.cannizzaro@nypost.com