Making the most dangerous leap in sales: Salesperson to Sales Manager

Jeffrey Gitomer is one of my all time favorite sales gurus. Here's a question from his recent newsletter that backs up my own personal thinking on what happens when you promote a salesperson to a sales manager. I'm not suggesting it can never work. I'm just recommending that you give serious thought to what you are losing and what you'll gain before you do it.
Gitomer.com

Question: Jeffrey, What are your thoughts on taking our best and senior salesperson and making him/her a sales manager? What are the benefits and downfalls of doing this? Michael

Answer: This is a great idea if you want to gain a bad manager AND lose your best salesperson. The most difficult jump in business, for two basic reasons, is from sales PERSON to sales MANAGER. The first reason is companies don’t train managers BEFORE allowing them to take the position. And second, the company doesn’t beef up the sales force to absorb the loss.