What If You Had a Poor Performer?

What if you had a poor performer on your team? How long is too long to carry them on the team?

One of my ducklings is leading a project. He has someone who is not performing and we are 2 weeks from the go live date on the project. As a mentor coach, I have recommended he remove the person from the project. The individual is not committed to performing at a high level (based on performance to date) and their poor performance will impact the project significantly. What would you do? How much longer would you attempt to coach this person through their obvious lack of commitment? Would you remove them? If so, how?

I am looking for serious advice. I will add an aside tomorrow morning with my recommendations for novices and experienced leaders. Today I am looking for your input. Help me help my young leader. I look forward to your recommendations.