Positives: Runs to the ball very well and has excellent quickness for a linebacker. A sideline-to-sideline player; can track down quick backs from the opposite side of the field. Safety-like in coverage, able to shadow tight ends and slot receivers. Also handles coverage responsibilities against running backs in the flat or on wheel routes. When running free, he closes fast, brings his hips and is a strong wrap-up tackler. Also uses his long arms to trip up ballcarriers on the move. Was a real force on special teams early in his career because of his speed and tackling ability. Played through knee pain throughout his senior season.
Negatives: Undersized, and some view him as a safety-linebacker "tweener." Not strong enough to get off blocks from linemen or fullbacks, and inconsistent against receivers. Does not keep cut blocks off his knees consistently. Will run around blocks inside instead of taking them on. Has the tools to be a good blitzer, but does not get home often enough. Could be effective in a stack system in which the defensive linemen protect him from blockers. Missed three games in 2008 with a knee injury and had surgery after the season.
Compares To: JARRAD PAGE, Kansas City -- If Casillas is moved to strong safety, his value to an NFL team will probably be much higher than as a weak-side linebacker, where he will be limited to just Cover-2 schemes. He has above average speed for either safety or linebacker and shows excellent sideline-to-sideline range. He plays faster than his timed speed and has a natural feel for tight ends, wide receivers and running backs in their routes. He plays with good instincts and makes plays in space. He will try to fill the rush lanes with no hesitation, but the results are marginal as he is generally mauled by the blockers due to a lack of playing strength. He plays under control and has a short burst to close and plays with good awareness working in the zone. He lacks natural hands for the interception, but he generates good acceleration coming out of his backpedal.
