Robert Frank Knoop (/kʌˈnɒp/ kuh-NOP;[1] born October 18, 1938) is an American former Major League Baseball second baseman and coach.

In another version, Knoop says the nickname derived from not only his acrobatic skills at second base, but a fabricated story he told the writers that his mother had made him take ballet lessons.

[6][8] He in fact played in every game that season and remained the Angels' regular second baseman for the next five and a half years (the name changing to California Angels in 1965), winning the club's MVP award four times in the span, a mark tied by Garret Anderson and Mike Trout.

[8][9] He turned the double play well along with shortstop Jim Fregosi, to give the Angels outstanding keystone defense.

[12] He is tied for the record of most double plays in a game by a second basemen, six, held with Alfonso Soriano and Bill Doran, which Knoop did on May 1, 1966.