I don't think anyone today would get past 7th grade pitching like that before his coach "fixed" his motion.
With his motion and power one would think that Johnson might have been susceptible to arm and shoulder injuries. However, Hank Thomas's excellent book (Walter Johnson: Baseball's Big Train) really only discusses a single serious arm injury in Walter's entire career. And there are many stories of Johnson, well into his retirement, pitching with speed that still wowed current major leaguers. In response to questions of whether he could still pitch he generally said that his arm felt great and was up to it but it was his knees that were not.
|