The Oakland Raiders signed first round-draft pick Khalil Mack to a contract on Thursday.

The four-year rookie deal has a fifth-year option and is fully guaranteed at $18.68 million, according to The team confirmed the signing but did not disclose terms.

The linebacker from the University of Buffalo is Oakland's first draft pick to sign and the second first-round selection in the NFL to sign since the draft was held last Thursday. The Chicago Bears agreed to terms with cornerback Kyle Fuller, the No. 14 overall pick, on Wednesday.

As a senior at Buffalo, the 6-foot-3, 251-pound Mack was named a first-team All American and led the Mid-American Conference with 10 1/2 sacks. In 48 career games for the Bulls, Mack had 327 tackles, 28 1/2 sacks, 75 tackles for loss and 31 quarterback pressures. He also forced an NCAA-record 16 fumbles.

---The Cleveland Browns moved quickly to offset the potential loss of wide receiver Josh Gordon, reaching contract agreements with veterans Miles Austin and Earl Bennett on Thursday.

With a season-long suspension looming after Gordon failed another drug test, the Browns reached out and grabbed Austin, a former Dallas Cowboys receiver, and Bennett, who played for the Chicago Bears. Gordon missed two games last season because of a drug suspension but still led the Browns with 87 receptions for an NFL-best 1,646 yards.

The 29-year-old Austin was named to the Pro Bowl in 2009 and 2010 after he turned in 1,000-yard receiving seasons, but his production with the Cowboys declined the past two years. Austin was limited to 24 catches for 244 yards last year because of hamstring injuries but still has a shot to become a starter right away with the Browns.

Bennett spent six seasons with the Bears and had 185 receptions for for 2,227 yards and 12 touchdowns. In 2013, he had 32 catches for 243 yards and four touchdowns.

---The Oprah Winfrey Network has purchased the rights to a new multi-part documentary series following the life of Michael Sam, who made history when he became the first openly gay player drafted into the NFL by the St. Louis Rams.

Terms were undisclosed, but reported Wednesday that negotiations to make the deal took two months. The network is working with Emmy-winning producer Craig Piligian and Emmy-nominated filmmaker Amy Rice.

Sam was picked in the seventh round of the NFL Draft on Saturday. Cameras for the network were with Sam when he received the call that he was drafted and will follow him through training camp as he tries to make the team. Meanwhile, the Rams said they were unaware of the project before drafting him and will limit camera crews to the media access that other rookies receive.

---The Tampa Bay Buccaneers officially announced on Thursday the hiring of Jon Robinson as director of player personnel and Andy Speyer as national scout.

Robinson comes to the Bucs after 12 seasons with the New England Patriots (2002-13), where he spent four years working with Buccaneers general manager Jason Licht (2002, 2009-11).

---The Chicago Bears and their third-round pick, defensive tackle Will Sutton, agreed to a four-year deal, the team announced Thursday.

All of the team's eight 2014 draft picks are now under contract. Sutton was twice named the Pac-12 Defensive Player of the Year at Arizona State, where he had 20 1/2 sacks and 45 1/2 tackles for loss.

---The Indianapolis Colts signed seventh-round pick and offensive tackle Ulrick John and inside linebacker Andrew Jackson, their sixth-round pick in the 2014 NFL Draft, on Thursday.

Jackson played college football at Western Kentucky. He appeared in 37 games during his career and started 33, finishing with 326 tackles, 6 1/2 sacks, 43 tackles for loss, one interception five forced fumbles, one fumble recovery and four passes defensed. John was a two-year starter at left tackle but also logged starts at center and guard earlier in his career.

The Colts also waived offensive tackle Erik Pike and cornerback Darius Polk.

---The Washington Redskins signed 10 college free agents, including Notre Dame quarterback Tommy Rees, the team announced Thursday.

The college free agents include Tulane nose tackle Chris Davenport, Southern wide receiver Lee Doss, Brigham Young wide receiver Cody Hoffman, Indiana wide receiver Kofi Hughes, Northwestern wide receiver Rashad Lawrence, Texas El-Paso tight end Kevin Perry, Southern California running back Silas Redd, North Dakota State defensive back Bryan Shepherd and Arkansas nose tackle Robert Thomas.

The Redskins also released wide receiver David Gettis and kicker Jake Rogers.

---The Buffalo Bills signed fourth-round draft pick cornerback Ross Cockrell and seventh-round picks linebacker Randell Johnson and offensive tackle Seantrel Henderson. Terms were not disclosed.

---The Green Bay Packers signed center Corey Linsley and wide receiver Jared Abbrederis, who were both fifth-round draft picks. Terms were not disclosed.