My theory as to why Tyreese isn't on the show yet [Comic Spoilers]

In the Comics Tyreese is basically the second in command of the Survivor Group behind Rick. they generally agree with each other, but butt heads occasionally, similar to the Rick/Shane dynamic in the Show

He is usually put in charge when Rick leaves the group for whatever reason, such as when he is put in charge when Rick , Glen, and Michonne check the helicopter wreckage during the prison arc.

Right now the role of second in command is being held by Shane, who in the comics doesn't live long enough to fulfill that role past the few issues he's in.

I think that its because Shane is still alive that Tyreese isn't introduced yet, because there are already two alpha males in the group vying for control, and adding a third would mess up the dynamic of the show.

I think that once Shane is killed, preferably in the same manner as he was in the comics, that Tyreese will be introduced the same way he is in the Comics, adding to the group what was lost with Shane, a strong reliable second in command.

The early interactions between Rick and Tyreese in the comic were interesting because of the bond they formed, even with Ricks initial hesitation because of the recent betrayal of his best friend.

TL;DR: Shane will most likely die at the end of this Season, and Tyreese will be introduced sometime in Season 3 to fill the second in command void that Shane leaves, in the same way it happened in the Comics.

Thoughts?