Matt Schaub has terrific size, strength, and a decent arm. He is an accurate passer (especially underneath) has a good release, and leads his receivers well. He has the ability to find the second receiver and he reads defenses well.
His footwork is inconsistent, but can be polished with good coaching. He lacks speed and mobility, and will not buy much time with his feet. He does not throw well on the run. Strictly a pocket passer.
Although he does not possess a cannon for an arm, Schaub's size and adequate arm are attractive enough for someone to take a shot at him in the third round. I don't see him being any better than a career backup in the NFL.