(Editor's Note: Training camp is an important time of year for the NFL's undrafted free agents, as unknown players will fight to earn roster spots all over the league. The Cowboys have an especially rich history with undrafted free agents, given the success of once-unknown players like Tony Romo, Cole Beasley, Lance Dunbar, Jeff Heath and Dan Bailey. This series will seek to preview this year's batch of undrafted rookies, as well as the challenge that awaits them at training camp. We'll continue the series with offensive tackle Ryan Mack.)

Name: Ryan Mack
Position: OT
Height/Weight: 6-4 / 304
College: Memphis

College Career: Was a key member of Memphis' offensive line in 2015, helping the Tigers to a 10-win season. Mack protected quarterback Paxton Lynch, one of college football's top passers last season. He transferred to Memphis from Louisville, where he was a regular starter for two years at right tackle.

Spring Synopsis:Mack has played both sides of the line so far in the offseason, which is a trait that could help him stick around. Being versatile is a key for any young player, especially on the line. Mack has good size for the position and will likely only add strength leading up to camp. The fact the Cowboys are willing to move him around is an indication there could be some potential to work with. Finding good, young offensive linemen isn't always easy and so the Cowboys might be a little more patient with a guy like Mack. [embeddedad0]

How He Makes It: Mack can make this roster if he shows the coaching staff he can be physical, flexible and dependable. He obviously can't get hurt and needs to take advantage of situations involving other tackles around him that might get banged up and miss practice time. The Cowboys are high on third-round pick Chaz Green, but he's had some injury issues in the past. Mack has to take all of the reps and play well in the second half of preseason games when his opportunity comes.

How He Doesn't: Like all of the rookie hopefuls, Mack won't make the team if he doesn't play well. While that sounds somewhat obvious, there are some guys on the team, maybe veterans or younger draft picks that will stick around even if they struggle at camp. But undrafted rookies don't have that luxury of having an off day or week. So Mack can't afford to get hurt, or struggle repeatedly in drills. The Cowboys have two starting tackles and currently plan on using Green and possibly veteran Charles Brown. If Mack doesn't prove he's worthy of keeping around over one of them, he'll likely not make this team.