I think this is the best written description of the typical work-place underachiever I have ever read:
… self-handicapping is when we put constraints in place before doing something, which we can subsequently use as excuses in case we fail in the future. Procrastination is an example of this. Think about a scenario where your boss gives you a task to complete with a deadline to do it. Rather than begin the task immediately, though, you leave it until the last minute – rationalizing that you were too busy with other tasks to do it before then. The real goal, though, is to establish an excuse in case your boss doesn’t like the result of your work. A self-handicapper can then blame the poor results on not having enough time to complete the task rather than on insufficient efforts or unremarkable abilities. Good performance may be lost, but self-esteem can be preserved.
From Psychology Today – Credit and Blame at Work