He's actually not a special ML pitcher, although he's not as bad as his ERA has been lately. But I wouldn't pay him $5M, either. While his VsR and control are good and they're the two most important ratings, his pitches, GB/FB, and VsL are mediocre.
In a large enough sample, which given his ST/DUR would be about 4-5 seasons, and if you ran his pitch count at 5/10, he'd have an ERA of about 3.30 in TAC (NL). Given that MikeT23 could pitch to an ERA of about 4.60 in Tacoma, 3.30 in 40-50 innings per season isn't that helpful.