put out to grass
Also, put out to pasture. Cause to retire, as in With mandatory retirement they put you out to grass at age 65, or She's not all that busy now that she's been put out to pasture. These idioms refer to farm animals sent to graze when they are no longer useful for other work.
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.