Calvin Johnson is the best receiver in the NFL, but as the Lions proved last year, even he needs a sidekick.

Nate Burleson broke his leg and missed most of the season. Ryan Broyles tore his other ACL and landed on injured reserve. Titus Young squandered his once-promising career with insubordinate behavior. And the Lions finished the year with three defenders plastered on Johnson and no one who could make teams pay on the other side.

Young's gone now, and though Burleson and Broyles are back and should be key parts of the passing game, the Lions' never-ending search for a No. 2 receiver goes on.

They drafted receivers in the second round each of the last two years, have taken four overall in Martin Mayhew's four seasons as general manager, and probably will take one again in this week's draft.

Not at No. 5. There's not a receiver worth taking that high. But at any point after that (including in a first-round trade-down), the Lions could go with a receiver.

So what are they looking for, besides someone who'll stick around longer than the two seasons Young (a second-rounder in 2011) and Derrick Williams (third, 2009) made it?

"I think with what we have on the roster right now I would say somebody that can stretch the field," quarterback Matthew Stafford said. "I think in the NFL, more and more today, everybody's looking for that. It doesn't matter if you're playing opposite of Calvin Johnson or not, you want somebody that can run."

The Lions hosted four receivers projected to go in the draft's first two rounds on pre-draft visits this year, and all fill the speed requirement.