The biggest domino that needs to fall for the Detroit Lions this offseason is getting an extension done with wide receiver Calvin Johnson. Because his cap number is so big for next season, the Lions need to work out an extension that will lower that number and free up space so they can make other moves.

While nothing had come out recently about the status of the negotiations with Johnson, Anwar Richardson reports that the Lions are close to making an announcement about an extension.

Being told #Lions are close to announcing a seven-year extension for Calvin Johnson #NFL

— Anwar Richardson (@AnwarRichardson) March 14, 2012

According to Richardson, Johnson is currently en route to Detroit and both he and the Lions "hope to make an official announcement today."

I really can't stress how big this would be for the Lions. Not only would they free up some cap space, but locking down Johnson to a seven-year extension would be just as important. He is the best receiver in football, and knowing he would be a Lion for the rest of the decade would be a very good feeling.

UPDATE: The deal is official. A press conference is scheduled for 1 p.m.