It has been confirmed that Pill Paxton (Big Love, Aliens) has been hired by Marvel to play Agent Jonathan Garrett in at least four episodes of Marvel’s Agents of S.H.I.E.L.D. this season. Garrett is said to be a Level 7 veteran S.H.I.E.L.D. agent, but beyond that it isn’t known exactly what his connection to the agents will be or exactly what his role in the organization is.
In the comics, John Garrett was introduced in the mid-80s as a character in the Elektra franchise. Eventually, his story was developed so much that it’s later learned he’s been around as long as Nick Fury, and was one of of the spy organization’s founders. He was also a cyborg.
It’s most likely that whatever they have in store for the character, he’ll start out as a normal human that’s there to boss around Coulson’s people. They’ve already built some superpowered characters out of the show this year, mostly villains, so don’t be surprised if Paxton ends up punching through walls sometime next season!