It's a tough situation to handle, because if someone is simply struggling at their job, it can have the same symptoms. They claim they have too much work to do,

It's a tough situation to handle, because if someone is simply struggling at their job, it can have the same symptoms. They claim they have too much work to do, and important projects always end up delayed, with their tasks being the ones that are delaying everyone. As a manager you need to make a judgment call about how much work they are actually taking on, but that can be tricky when you're less familiar with the codebase than the individual is. Either way, you still want to move critical tasks off their plate.