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The Mariners think that Morrow could move quickly because of his advanced approach and, of course, his refined stuff, especially for someone with his age and experience.

"His offspeed pitches are very refined for a younger kid," Rice said. "He throws strikes with his split-finger and breaking ball. A lot of times, a kid might be able to spin it pretty good but not throw strikes. But he's able to command those pitches very well. You don't see that a lot from a young kid.
I agree with Rice when it comes to Brandon Morrow. He is very composed for a young guy just coming out of college. His stuff is electric and could be the good compliment to King Felix in about 1-3 years. The soreness in his arm will be watched really closely. Mariners management will treat him like they did fellow flamethrower Felix Hernandez to ensure he doesn't fall to that dreaded curse of great SP prospects falling apart.