Ever since the NFL's three-day negotiating window for free agents opened on Saturday, the Green Bay Packers have found themselves being plenty busy.

It didn't take them long to come to terms with cornerback Sam Shields, reportedly agreeing on a four-year, $39 million contract, assuring Shields will stay in Green Bay for the prime of his career.

Some might argue that the Packers overpaid for a player that has yet to be named to a Pro Bowl, but the Packers also paid the price for what they project Shields to be in the future, which ostensibly includes him being a Pro Bowl caliber corner.

The Packers, along with about a half dozen other teams, have also been in negotiations with tight end Andrew Quarless, according to Tom Silverstein of the Milwaukee Journal Sentinel.

There's been no indication that Quarless is close to signing with any team, including the Packers, but that could change at a moment's notice. He and any of the team's upcoming 16 unrestricted free agents can re-sign with the Packers at any time, although they must wait until free agency officially opens on Tuesday afternoon if they hope to sign with another team.

The one-year offer of $4 million for defensive lineman B.J. Raji is apparently still on the table from the Packers, and Raji is weighing his options.

He can either come back to the Packers on a one-year "prove it" deal and hope to strike it rich in free agency again next season or look for the security of a multi-year deal with another team.

As for players from other teams, the Packers are reportedly interested in a pair of defensive lineman, perhaps hedging against Raji's potential exit.

Nothing is imminent, but the Packers have apparently at least expressed interest in defensive linemen Lamarr Houston of the Oakland Raiders (according to Ian Rapoport of the NFL Network) and Arthur Jones of the Baltimore Ravens (according to Aaron Wilson of the Baltimore Sun).

Both players have also gained interest from other NFL teams as well, so the Packers are just one of several suitors.

There's probably been plenty of other negotiations that have taken place behind closed doors as well, information that hasn't been leaked. Even though it hasn't been reported since the three-day window opened, it makes sense that the Packers would be in touch with players like center Evan Dietrich-Smith and fullback John Kuhn.

Free agency officially opens at 3:00 p.m. CT on Tuesday.

Also on Monday, scouts of the Green Bay Packers will be in attendance at several college pro days. Among the universities holding theirs are: South Florida, Troy, Grand Valley State, San Diego and Villanova.