Got a son? Teach 'im to throw left
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=== Hit 'im With So Many Lefts He Begs for a Right, Dept. ===
Followup question: how did the above 12 pitchers do in their first seasons? Were Jon Lester, and Cole Hamels, and Ricky Romero, effective in their rookie seasons?
You can find hard-throwing LHP's who are not effective, and it's because they have terrible mechanics and they're wild. Wild in putting guys on base and then wild in centering fastballs. But you get a lefty throwing a real quick fastball, and he's got a good K/BB ratio ... well, he's got some hard blinkin' work ahead if he wants to get his ERA+ under 110.
But you take James Paxton, and he's not throwing 90 or 91 mph. The reports are that he's touching upper 90's. Upper 90's? Well, suppose he's not throwing 96. Suppose he's throwing 93. Where does that fit on the above chart?
Reports are, he's the 5th LHP who throws above 93, along with Sabathia, Price, Kershaw and Holland.
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=== Whydat?, Dept. ===
About 30% of major league pitchers are lefty, but only about what, 12% of the general population are lefty. That means that a much larger fraction of left-handed people get to pitch in the bigs than right-handed people do. RHP's are selected against very strongly. It takes +2 or +3 MPH on their fastballs to make the cut.
So hitters are used to seeing 92 from RHP's, but only 89-90 (tops) from LHP's. Erik Bedard's fastball is what they're used to dealing with from that side, not Michael Pineda's.
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Can you really generalize that so much? Be lefty, throw 90-94, put together a decent pro game and you're in like flint? Sure. Check the above table. Or here are the fastball velo leaders from 2009. Find me the LHP on it, who wasn't effective. There are zero of them. Or here's the list from 2006: All the same pitchers, plus Johan Santana and Erik Bedard...
You might ask, why don't all 94 mph lefthanders get taken in the first round. Well, all the polished ones do. When's the last time you saw a 94 mph lefty, with a good K/BB, get underhyped? If he throws hard and has a K/BB ratio, he is Matt Moore getting a long contract after 10 innings, or NYY prospect Manny Banuelos, or he's going #2 in the draft like Hultzen, or something.
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This doesn't make James Paxton a mortal lock to --- > go 17-5 as a rookie, like Sabathia did, or 16-6, like Lester did, or 15-5, as Hamels did in his first full year, or 21-5 as Kershaw did last year at age 23.
I'm not saying Paxton is a guarantee. But now you got a feel for the situation. Don't paint James Paxton with a garden-variety prospect brush. C.C. Sabathia didn't show anything that Paxton hasn't shown.
BABVA,
Dr D