To help preview who might be on the Dallas Cowboys’ board for the NFL draft, ESPNDallas.com has identified five players at five key positions that we’d like to learn more about. Along those lines, we’ve asked former Cowboys assistant coach Glenn “Stretch” Smith – the official scout of Galloway & Company – to study tape of each player and give his thoughts.

No. 3 offensive lineman: Lane Johnson

Position: Tackle

Height/weight: 6-foot-6, 303 pounds

School: Oklahoma

Why he’s on the radar: Left tackle Tyron Smith had a good season for the Cowboys last year, but inconsistent play from right tackle Doug Free prompted the team to use Jermey Parnell. The Cowboys need to upgrade the offensive line, and if Johnson is available in the later half of the first round, he would be a good choice. Johnson played both tackle spots at Oklahoma and multiple positions in high school -- from quarterback to defensive end, so athletic ability isn't an issue.

Projection: First round

Stretch Truths: Tall tackle plays with excellent leverage and can play all positions across the line. ... Smart football sense; good punch and power; can reach block; good straight in-line run blocker. ... Has power to sit and stop a bull rush. Also has good balance to recover in pass protection. ... For a big tackle, he can really run, as evidenced by his 4.67 40-yard dash at the NFL scouting combine in Indianapolis. ... Take him if he's there with the 18th pick.