The emergence of the spread passing game at all levels of football has resulted in two very different types of receivers needed to execute it. Outside receivers are used (for the most part) to stretch the field vertically and generate big plays via longer routes. Inside receivers or slots have basically replaced the tight end in the passing game as they typically work between the hashes and stretch the field horizontally. They must have extremely quick feet in order to get separation since they work the heavy traffic areas in the middle of the field where holes in the coverage open and close quickly. Their athleticism enables them to obtain mismatches versus bigger linebackers and safeties and they can also be usefully employed on handoffs, bubble screens, and as return men.
For the most part, slots act as a safety valve for quarterbacks. You'll occasionally see one on a seam route or smash down the field but most of the time they'll emerge from a game as a team's leading receiver with five plus catches and averaging 10 to 12 yards per catch (in comparison, outside receivers usually average closer to 15 yards per catch).
This year's class within the state of Texas is headlined by Foreman, who averaged 27 yards per catch as a junior and an unearthly 20 yards per rush, generating a touchdown every five touches on offense. He is a big play guy who can get downfield which is a premium for the team that lands him. His on field speed, acceleration, and elusiveness are off the charts. In particular, his acceleration is just unbelievable. Not only that, he's got great hand/eye coordination, looks every pass into his hands, and makes every catch seem routine even on passes thrown behind him. He's versatile enough to be offered as both an inside receiver by Texas A&M and an outside receiver by other programs. He's the closest person in the class from a skills standpoint to 2013 Cedar Hill athlete Quiv Gonzalez but is a far superior receiver.
Jeffrey earned his offer from Texas A&M last fall by putting on a four touchdown performance against A&M Consolidated in front of A&M coaches who were scouting the game. However, his most spectacular play in that game wasn't even a touchdown. He took a bubble screen on the left side and found himself in the grasp of one defender with three more waiting behind him. Jeffrey broke his tackle, broke the tackle of a second guy, spun back toward the right, broke a third tackle, outran most of the defense to the opposite hash about ten yards downfield, and then broke two more tackles before finally going down. His elusiveness, change of direction, and balance on that play alone were probably enough to secure the offer.
Bernard is a true slot receiver. He lines up on the inside rather than the outside in high school and so he doesn't need to make a transition to the position. He's a track guy and can simply blow by people if he has to. He also has great acceleration and can catch hitches and screens, make people miss, and get down the field quickly. At the Houston Rivals Camp, he displayed quick feet, a good change of direction, and the ability to adjust to balls in the air.
Avery plays running back but will be a slot at the next level. He generated 20 touchdowns on runs, receptions, and returns last season. He's got great balance and deceptive speed and hits his top gear before you realize it. As an example, he caught a bubble screen on his own two yard line last season, made a defender miss, and proceeded to outrun the rest of the defense en route to a 98 yard touchdown.
Williams is an undersized guy even in comparison to prospects who play slot. However, he's true 4.4 sprinter who can get downfield in a hurry as evidenced by his average of 17.5 yards per reception and ten touchdowns on just 45 receptions. He plays on the outside in high school but due to his speed rarely faces press coverage, something he's got to be prepared for at the college level due to his size.