With the NFL rookie portion of training camps having started for some teams and full training camps for everyone starting up in a few days, several first round picks are still unsigned. These include three of the top six picks, Solomon Thomas of the San Francisco 49ers (3rd overall), Corey Davis of the Tennessee Titans (5th) and Jamal Adams of the New York Jets (6th).

Why the 49ers selected Solomon Thomas

The San Franciso 49ers selected defensive end Solomon Thomas out of Stanford in order to bolster their especially porous run defense, which allowed 165.9 rushing yards per game last year.

That was the worst in the NFL, with the 49ers allowing 23.2 more yards per game than the next closest team in the Cleveland Browns. Thomas showed he can get to the quarterback last year, racking up 8.5 sacks in his final college season.

Why the Titans selected Corey Davis

The Tennesse Titans picked wide receiver Corey Davis out of Western Michigan in order to surround the young and talented quarterback Marcus Mariota with better weapons. Last year, Davis was one of the best receivers in college football, racking up 97 receptions for 1,500 yards and 19 touchdowns.

He was selected MAC Offensive Player of the Year and was a consensus All-American. Unfortunately for the Titans and 49ers, both Davis and Thomas are represented by the same agency as Joey Bosa, who held out until the end of August and missed the first four games last season.

Why the Jets selected Jamal Adams

The New York Jets selected Jamal Adams out of LSU in an effort to bolster their flimsy secondary, which allowed 30 touchdowns (T-5th worst) and only got 8 interceptions (T-2nd worst). The team traded Calvin Pryor and parted ways with starters Darrelle Revis and Marcus Gilchrist. Last season at LSU, Adams recorded 76 tackles, 1 sack, 1 interception and had 1 forced fumble.

Other three unsigned first rounders

The other three first-round picks to remain unsigned are Kansas City Chiefs quarterback Patrick Mahomes II (10th overall), Oakland Raiders cornerback Gareon Conley and Cleveland Browns safety Jabrill Peppers. The Kansas City Chiefs have recently fired and then hired a new general manager, which could partially explain Mahomes being unsigned.

Conley and Peppers are fully guaranteed their whole contracts, as that is guaranteed up to the 21st pick of the NFL Draft. Conley is also dealing with a serious off-field issue that may be holding up his signing.