Oh no no no no.....they're not dumb enough to get rid of Darrell. Darrell rocks, and I suspect TPTB have picked up on that fact. Rick and Darrell are headed for bromance city.
I've never read the comics, but I suspect he'll be like a lieutenant to Rick and be the friend Shane never was. Hell, he's definitely not in love with Olive Oyl, so the bromance should be smooth sailing.