In a bit of a shocking move, the San Francisco 49ers traded center Daniel Kilgore to the Miami Dolphins on Thursday. What did they receive in return? The 49ers moved up a whopping four spots in the seventh round of April's draft from the 227th-overall selection to No. 223.

After not receiving much in return for a starting NFL center, you may be wondering why the 49ers would make the trade when the team has a large surplus of salary cap space and a need for interior offensive lineman. A report by Travis Wingfield of the "Locked On Phins" podcast states that Kilgore requested the trade after San Francisco signed free agent center Weston Richburg to a five-year deal worth $47.5 million. The 49ers reportedly asked Kilgore to move to guard, which he did not want to do.

The trade comes a month after Kilgore signed a three-year extension worth $11.78 million with $7.05 million guaranteed. Albert Breer of The MMQB notes that the 49ers structured Kilgore's deal so that his first bonus would not be due until the third day of the league year (Friday), which protected the team should they find someone better to start at center.

The report, while unconfirmed, would make sense. It was believed that Richburg and Kilgore would compete for the starting center job with the loser moving to guard. It would seem the 49ers always intended for Richburg to be the starting center for the team.

Kilgore has been with the 49ers for seven seasons. Only tackle Joe Staley has been with the team longer (11 seasons). The Dolphins, who will take on all of Kilgore's contract, had a need at center after long-time starter Mike Pouncey requested to be released.

h/t to Patrick Tulini for the find.