Linebacker/Defensive End James Cowser

Outside of a team's draft picks, Rookie Minicamp is largely comprised of unknown players trying make an impression and earn a shot to make the roster during Training Camp.

The Oakland Raiders' Rookie Minicamp was no different, as 18 undrafted free agents and roughly 20 tryout players hit the field this weekend at the team's Alameda, Calif., facility for three days hoping to put their best foot forward and show the coaching staff that they were worthy of continuing their football careers in Silver and Black.

While it's easy to pinpoint the Jihad Wards and Shilique Calhouns of the world as players who stood out over the weekend – which they did – let's look at four under-the-radar-players who also impressed during Rookie Minicamp.

1. Defensive End/Linebacker James Cowser

The Raiders signed Cowser as an undrafted free agent, and the former Southern Utah Thunderbird definitely made his presence felt during Rookie Minicamp.

With long blonde hair flowing out of the back of his helmet, he's a hard man to miss on the field, especially when he's constantly around the football inserting himself into the action.

In addition to his knack for finding the ball, Cowser also showed that he's unafraid to take a vocal leadership role, routinely talking with Jihad Ward and other members of the defensive line in between plays about what the offense was going to be running.

Cowser may be on the older side for a rookie trying to make an NFL roster – he's 25 years old – but with the type of production he had in college and what he flashed during Rookie Minicamp, he's assuredly a player to keep an eye on.

2. Wide Receiver Jaydon Mickens

On the offensive side of the football, Mickens was a player who stood out to me since Day One of Rookie Minicamp.

While he may not boast prototypical size standing at 5'10" and tipping the scales at 174 pounds, Mickens is exceptionally quick, and if his college production serves as any indication, he knows how to catch the football and make plays.Mickens flashed his quickness and speed on several occasions over the weekend, and also showed that he has value as a kick returner, which could surely work to his benefit as the Offseason Workout Program progresses.

3. Defensive Tackle Darius Latham

Latham certainly looks the part of an NFL defensive tackle, weighing in at just over 300 pounds.

However, in addition to his pure size, he's surprisingly quick for a big man, and showed that he's willing to learn and get better, spending some time one-on-one with defensive line coach Jethro Franklin, working on his technique on a bevvy of pass rush moves.

It's no secret that the Raiders are stacked along the defensive line, but as Head Coach Jack Del Rio always says, you can never have enough players who are disruptive and can get after the quarterback.

4. Wide Receiver Max McCaffrey

While McCaffrey may not be flying too far under the radar – he was one of the team's most talked about undrafted free agent signings – he was certainly impressive during Rookie Minicamp.

The former Duke Blue Devil is still an unfinished product and will need to spend some time in the weight room during the offseason, but he can definitely catch the ball and is a player to keep an eye on as the team prepares for Training Camp 2016.

While the three-day whirlwind was certainly overwhelming for the rookie participants, McCaffrey looked comfortable on the field, running through drills with ease and flashing impressive footwork.

His highlight of the weekend came Sunday as he made an impressive diving grab during one of the team's seven-on-seven sessions.