There are two sides to Sean Mannion. How you feel about him largely depends on if you're a glass half-full or glass half-empty type of person. There really isn't a lot of middle ground to the Oregon State QB, but there is potential. How much and how long it will take to get there, are the questions I'll be trying to answer.
Here is Mannion against Utah. Not a terrible defense by any stretch - headlined by now NFL draftees Eric Rowe and Nate Orchard. Mannion throws the ball with some good velocity, but it's a bit high (a re-occuring problem, but more on that later) causing the WR to take a hit he didn't necessarily need to. Still, it's a good throw into a small window by Mannion:
On the very next play, he does this:
The problem here is that Mannion throws right off his back foot and uses his arm strength alone to force the throw in. When people say he doesn't have a strong arm, they clearly didn't watch him, because on many plays he's not using his lower body to generate any power at all. This happens on many occasions and it's a major technical flaw that will need to be fixed before the 'project' label is taken off.
Let's take a look at another set of back-to-back plays during the Utah game:
This is a terrible decision by Mannion. The cornerback was glued to the receiver nearly the entire time, but the compounding issue is again, his delivery. Mannion doesn't plant his feet again and the result is nearly an interception. The saving grace? Here's the next play:
the corner is straight torched on the play. Mannion sees it and delivers a good pass down the field for a huge gain. The difference? No pressure. Mannion's technical ability seems to disintegrate as he faces pressure, which is a big problem the Rams will have to work on. The ball floats a little, but considering it's a 50 yard pass, I don't think of it as a big deal.
Let's move to OSU's game against Hawaii. Here's another example of Mannion, with time, making a good throw in a small window:
Sensing a trend here? Here's a play-action pass against Hawaii where Mannion is pressured immediately and tries to dump it off to the fullback. The problem here is that he throws it nowhere near the fullback:
Oops. Once again we see the technical flaws coming out when Mannion is faced with pressure. I'm not sure if you'd call this a jump throw, but it looks like he throws the ball with neither of his feet on the ground. Take the sack and live another day.
Mannion is a decent development prospect at QB. He's got the physical tools and experience you look for in a pro-style QB. He also has the arm to make some pretty impressive down field throws. However, he needs major development before anyone can think of him as a starter. He needs to tighten up his throwing motion in the pocket so he can consistently generate more power and deliver the ball more accurately.
He also needs to work on his instincts - when under pressure, he tends to revert to sloppy footwork and lazy technique, leading him to throw many balls high, or in the last case, completely off the mark. That may work against teams like Hawaii and Utah, but it's not going to work in the NFL.
Mannion may have long-term potential, but he isn't ready for prime-time just yet.