It's not that good mechanics "can help". It's that they are usually the deciding factor between a long, productive career and Mark Prior/Anthony Reyes.
Probably Gray, Smyly, Paxton, Archer. The Rays are known to deal from their pitching depth (and they're deep in SP when a couple other surgery guys come back).
The Sox (Papi and Betts especially) own Archer hard. He's 1-7 with a 5.67 ERA against the Red Sox.
All Porcello has to do: Not f*** this up!
He has a 3.09 ERA vs the Rays. Hopefully those trends continue.
That could not be farther from the truth. Guys with inverted W's and L arm actions, as well as guys who throw a very high percentage of breaking pitches are significantly more at risk for elbow/shoulder troubles than guys with cleaner mechanics and are not as over-reliant on breaking pitches, like Kluber. Any pitcher is liable to break down at any moment, but the risk percentage is significantly higher for some guys than others. Chris O'Leary's work is a good barometer of the importance on mechanics as a barometer for probability of injury.
Syndergaard, Kluber, Salazar, Smyly, Gray, Bumgarner, Archer, Paxton, Stroman, Kershaw, Urias, Giolito, et al. All come with inherent risk, but youth/cleaner mechanics than some of the guys I always say "Oh God no" to.
The Marlins are thin at IF. Moncada is probably the headliner of any Fernandez deal, and I would not do it. Fernandez is a high-maintenance mechanics guy who throws a lot of breakers, has already had TJS, and doesn't provide the IP bulk of a true top-end guy. No thanks.