Daniel Kilgore’s mind was at ease on Feb. 14 after signing a three-year contract extension to remain with the 49ers – the team that selected him in the fifth round of the 2011 draft.

But all that changed on the first day of the open negotiating period when he learned the 49ers reached an agreement with New York Giants free-agent Weston Richburg on a five-year contract. The same firm, Rep1, represents Kilgore and Richburg.

“Originally, I knew Weston was on the Niners’ board for left guard,” Kilgore said on the 49ers Insider Podcast. “When I knew that he was going to sign with the 49ers, I was thinking, ‘Hey, we just got a new left guard.’ I hate it for Laken (Tomlinson).

“But, then, you kind of find out he was coming for center. That’s when I was thrown for a loop.”

Kilgore described the days that followed as “crazy,” “frustrating” and “heart-breaking.”

One day after the 49ers officially signed Richburg to a five-year, $47.5 million contract, Kilgore was traded to the Miami Dolphins. The 49ers got little in return for delivering Kilgore to what appears to be a good situation. The team’s swapped draft spots in the seventh round, with the 49ers now choosing at No. 223 overall, while the Dolphins pick at No. 227.

Kilgore lands in a situation to be a starter. He also received, in essence, a 13.3-percent raise for leaving California to go to Florida, where there is no state income tax. The 49ers structured Kilgore's contract so the first payout of a $2.3 million roster bonus was scheduled for after the start of the new league year – after the trade. The Dolphins pick up the entirety of the three-year, $11.75 million contract the 49ers negotiated with Kilgore.

Kilgore said he was never asked to compete for a job at guard with the 49ers. He said he did not request a trade, either. He was told, in essence, he was no longer in the 49ers’ plans.

General manager John Lynch told NBC Sports Bay Area last week both Richburg and Kilgore are best at center. To ask either to submit to a change of position would set up one of them for failure.

Looking back, Kilgore said he wonders if he should have turned down the 49ers’ offer and gone into free agency. But that approach had its risks, too. All he wanted, he said, was to be compensated fairly and remain with the 49ers.

“I was really thrown for a shock,” said Kilgore, who won the Bobb McKittrick Award last season for his displays of courage, intensity and sacrifice. “You just wonder, ‘What If I did go free agency?’ (But) that wasn’t me. I knew where that team was going. I’m familiar with the area, familiar with the coaching staff, my best friends are on the team. So I knew this is where I wanted to be. I didn’t see myself going anywhere else.”

Now, he will be moving to South Florida, where he will attempt to establish what he felt he had with the 49ers.

“You want to be there and be a part of something on the rise," Kilgore said. "That was the frustrating thing, that you’re no longer going to be there. It’s frustrating and heart-breaking, but you move on. I’m going to South Florida, and that makes things a heck of a lot better.”

Kilgore said he had some hard conversations with Lynch and coach Kyle Shanahan last week. Ultimately, he said he respects both men for the way they handled an awkward situation. Lynch said last week when the 49ers signed Kilgore to an extension, the club believed there was a likelihood Richburg would not still be available a month later as a free agent. Richburg was the only center the 49ers would have sought to replace Kilgore, Lynch said.

“I hope the fans out there know the truth about everything and know that Kyle and John did it in the best interest of me and the best interest for the team moving forward,” Kilgore said. “There’s no bad grudges or anything like that. We’re all still friends at the end of the day.”