Joes87,
In the interest of accuracy... Many of the games best professional pitching prospects are pitching in winter leagues. While their innings might be monitored they have not shut down. Many will have a very short time to shutdown before spring training.
So to say every MLB pitcher shuts down for 60-90 days every year, simply isn't true. It's really hard to tell anyone that, when Winter and Fall Leagues are being played in Arizona, Latin America, Mexico and Australia.
I do agree with a shut down period, just saying it doesn't always happen the same way for every pitcher.