It's a quarterback league, everybody knows that. That also means that the NFL is a receiver league, because somebody has to catch all those passes - and ideally break a tackle or two afterward.

There is an especially deep class of receivers at this year's NFL combine, and those receivers will fly off the shelf at the draft, with as many as nine being picked in the first two rounds. They were flying on the field at Lucas Oil Stadium on Sunday, as eight receivers turned in a time of 4.43 seconds or better in the 40-yard dash.

Among the interested spectators were 49ers general manager Trent Baalke, who needs a fast receiver to stretch the field and open up things for the rest of the offense. Raiders general manager Reggie McKenzie also was transfixed by the precedings, as Oakland's last 1,000-yard receiver was Randy Moss in 2005.

Oakland picks at No. 5, and could have the option of taking the top receiver available, Clemson's Sammy Watkins. He's 6-foot-1, attacks the ball in the air and runs very well - evidenced by his 4.43 time Sunday.

"Watkins is a special player, and I usually don't get too excited about wide receivers in the top 10, but this kid is different," said NFL Network draft analyst Mike Mayock. "He's got great hands. ... What I really, really liked about this kid is, he's got toughness. He'll physically beat press coverage."

The Raiders have so many needs that they might pass on Watkins and get another receiver or two later in the draft. The 49ers pick 30th and could grab a deep threat to team with possession-types Anquan Boldin and Michael Crabtree.

With Watkins, USC's Marqise Lee, Texas A&M's Mike Evans and Florida State's Kelvin Benjamin probably gone by then, the 49ers could choose from three deep threats who made whooshing sounds Sunday.