NFL Draft Raiders Football

Wide receiver Amari Cooper, the first round draft pick of the Oakland Raiders, center, holds up a jersey between general manager Reggie McKenzie, left, and head coach Jack Del Rio after a news conference in Alameda, Calif., Friday, May 1, 2015.

(Dan Honda/The Oakland Tribune via AP)

A day before opening mini-camp, former Alabama star receiver Amari Cooper signed his first NFL contract.

The four-year deal with the Oakland Raiders will pay Cooper $22.7 million fully guaranteed. That includes a $14.7 million signing bonus, AL.com learned. His base salary will be $435,000 as a rookie, escalating every year to $3.5 million in the fourth season. The team also has a fifth-year option.

Cooper was the fourth pick of the NFL Draft a week ago. His contract is more lucrative than last season's No. 4 pick, also a receiver. Sammy Watkins got $19.9 million guaranteed and a $12.8 million signing bonus from the Bills last year.

The contract was enough to make the typically stoic Cooper smile.

The Oakland Raiders have signed WR Amari Cooper, the Raiders 1st round selection in the 2015 NFL Draft. pic.twitter.com/W1uxweDeH6 — Oakland Raiders (@Raiders) May 7, 2015

Two of Cooper's former teammates also signed rookie deals Thursday. Offensive lineman Austin Shepherd got a non-gauranteed deal for $2.3 million, according to the St. Paul Pioneer Press. That includes a nearly $70,000 signing bonus for the seventh-round pick.

Linebacker Xzavier Dickson, also a seventh-round pick to New England. Financial terms were not immediately available.