Nobody has to tell Bob McAdoo he's not wanted.

The three-time NBA scoring champion has informed Coach Richie Adubato that he no longer enjoys playing for Detroit (after a whole three-fourths of one season). "He said," Adubato relates, "that he feels disheartened and that we're a young team and going nowhere this year. I feel that there's no sense playing a guy who's unhappy." So Adubato benched McAdoo for the Boston game Sunday and the Pistons indicated they would gladly trade Big Mac if the opportunity arises.

A trade would send McAdoo to his fifth team in less than four years. . . .

Kevin Keegan, the English soccer stylist voted Europe's footballer of the year in 1978 and 1979 -- and the object of the Washington Diplomat's affectionate attention -- evidently won't be coming the NASL route, for now. When his three-year contract with Germany's SV Hamburg runs out June 30 he will join Southampton of the English First Division, he announced yesterday. It's a reported $900,000 deal.

Renaldo Nehemiah will compete in Madison Square Garden this season after all. Hurdling's nonpareil has entered the TAC-AAU meet Feb. 29; so has Terp teamamte Chris Person, a surprise winner of the 600 in last weekend's Millrose Games in the Garden. . .

One more pitcher? Gaylord Perry says in Williamston, N.C., he will be serving 'em up again this summer, at 41. But not for San Diego, which has him under contract.