The Legion of Boom's uncertain future has made defensive backs a popular first-round projection for the Seattle Seahawks. ESPN draft analyst Todd McShay continued that trend in his third mock draft, which was released Wednesday. It has Seattle taking Iowa cornerback Josh Jackson at No. 18.

Before we go any further, here's the obligatory mention that the Seahawks don't have picks in the second or third round. That, plus general manager John Schneider's history of trading back in the first round to acquire more picks, makes it seem as likely as ever that Seattle will do that again instead of picking at No. 18. But mock drafts generally don't account for the likelihood of trades, so play along here...

McShay calls Jackson, a converted wide receiver, a "big-time ballhawk" and notes that he led the nation in interceptions as a junior last season with eight. That was along with 26 passes defended. ESPN college football analyst Brock Huard used that same term to describe Jackson -- "ballhawk" -- and also called him a disciplined player. Mike Mayock of the NFL Network said Jackson has the best hands of any defensive back in this year's draft.

Jackson's time in the 40-yard dash at the scouting combine was an unspectacular 4.56 (the same as Richard Sherman in 2011). But he posted 18 reps at 225 pounds on the bench press, which is good for a cornerback.

As for his size, which is a big deal for Seahawks cornerbacks, Jackson measured a little over 6 feet and 196 pounds with an arm length of 31 1/8 inches. While that height and weight fit Seattle's specs at the position, the arm length might not. As detailed here, every cornerback Seattle has drafted under Schneider and coach Pete Carroll have had arms measuring at least 32 inches. So if that number is their minimum requirement, the Seahawks may not feel that Jackson has quite the length they prefer.

Jackson is the No. 2 cornerback on Mel Kiper's Big Board. In McShay's first-round scenario, he's the fourth cornerback off the board behind Alabama cornerback/safety Minkah Fitzpatrick (Browns at No. 4), Ohio State's Denzel Ward (Bears at No. 8) and Central Florida's High Hughes (Redskins at No. 13).

McShay had Seattle taking LSU running back Derrius Guice and then Hughes in his first and second mock drafts, respectively. His last two mock drafts have left Guice out of the first round.

Kiper, meanwhile, had Seattle choosing Florida State safety Derwin James in his first two mock drafts. But after James' strong performance at the combine, Kiper's latest projection has him long gone by the time the 18th pick comes around.