Not so fast. I "saved" guys from being fired by asking to be more patient with them. The last one was not in my team as I moved out to lead another team. Turned out the guy did not please an influencial team member, who then complained about him.
What I saw instead was a young silent guy, given boring work and was longing for more interesting work. A tad later he took ownership of a neglected project, completed it and made a name of himself.