Should I cut Caron Butler and Gilbert Arenas?

My fantasy bball team is 4 games ahead in 1st place. I have both Caron Butler (labral tear, hip) and Gilbert Arenas (knee surgery) on my roster. Should I cut either one of them and pick up a free agent (Mehmet Okur, Raja Bell, Ryan Gomes, Troy Murphy, Larry Hughes) or just hold on to them and hope for the best in the playoffs? My team has been winning without them, but I fear an upset in the playoffs.