Mark Sheppard returns to Leverage on the summer 2011 finale. The actor portrays the character of Jim Sterling.
This doesn't look like an ideal situation. Nate is held at gunpoint on the Leverage summer finale.

Leverage Season 4 Episode 10 Quotes

Hardison: Because of its atomic mass, this thing is the nuclear version of "the one ring"
Sophie: Ring? What ring?
Nate: Don't get him started.

Nate: You still haven't said what's in it for me.
Sterling: I will owe you a favor. How often does that happen?