Steven Robert Ontiveros (born October 26, 1951) is a former third baseman in Major League Baseball who played from 1973 through 1980 for the San Francisco Giants (1973-1976) and Chicago Cubs (1977-1980). He also played six seasons in Japan for the Seibu Lions (1980-1985). Ontiveros was a switch-hitter and threw right-handed. He is of Mexican American descent.

A solid third baseman with an average arm, Ontiveros was named Minor League player of the Year by The Sporting News in 1973. He reached the majors with the San Francisco Giants late in the season, spending four years with them before being traded to the Chicago Cubs, along with Bobby Murcer, for Bill Madlock before the 1977 season. 1977 ended up being his most productive season for the Cubs, when he posted career-highs in games played (156), batting average (.299), home runs (10), RBI (68), hits (162), and on-base percentage (.390).

On April 17, 1977, Ontiveros broke up a no-hit bid by the New York Mets' Tom Seaver with a bloop single in the fifth inning. It would be Seaver's fifth career one-hit game before finally pitching a no-hitter in 1978 against the St. Louis Cardinals with the Cincinnati Reds. Ontiveros would join Jimmy Qualls, Mike Compton, Leron Lee, and Vic Davalillo as hitters who had broken no-hit bids by Seaver before his no-hitter.

In an eight-season career, Ontiveros was a .274 hitter with 24 home runs and 224 RBI in 732 games. Following his majors career, he played in Japan with the Seibu Lions from 1980 to 1985 and hit .312 with 82 home runs and 390 RBI.

[ Source: Wikipedia ]