turn (someone or something) out to grass
1. Of an animal, to give it access to a grassy area to graze. Tommy is putting the cattle out to grass. Should be back in a minute.
2. Of a person, to force, coerce, or pressure into retiring from their work. The CEO was shaped the company into what it is today, but she's getting on in years and the board of directors has decided to put her out to grass. It's high time that the team's manager is turned out to grass.
3. Of a piece of equipment, to retire from use or replace with something newer. I got through my entire graduate degree on this clunky old laptop, but I think it's finally time to put it out to grass.