Pitchers make too much money so they are reluctant to hit. Even if they are naturally good hitters (there are a couple). That's the downside of them making all that dough. Pitchers are specialists.
Pitchers didn't get paid too much money back in the old days so they were willing to hit the ball. But if they have a 100 million dollar arm? Forget it.
Who was the last pitcher to get injured during an at-bat?