Charles Oscar Hartenstein (born May 26, 1942 in Seguin, Texas) is a former relief pitcher in Major League Baseball who played for five different teams between the 1966 and 1977 seasons. Listed at 5 ft 11 in (1.80 m), 165 lb (75 kg), Hartenstein batted and threw right-handed. He was signed by the Chicago Cubs in 1964 out of the University of Texas at Austin.

A Texas Longhorns star pitcher, Hartenstein led his team to the 1962 and 1963 CWS tournaments. After being signed by Chicago, he led the Texas League with a 2.19 ERA in 1965 while pitching for the Dallas-Fort Worth Spurs.Chuck was involved in one of the most amazing pitching feats in Texas League history. On June 17, 1965 Chuck started the game against Austin (Texas). The Spurs had a lead, 1-0, going into the 9th inning when Chuck gave up a tying run. The game continued that way with Chuck pitching 18 (!) innings. He had allowed one run, eight hits, walked four and struck out seven. The game continued through the 25th inning with Austin winning 2-1. At the time it was the longest game in Texas League history.

Hartenstein entered the majors in 1966 with the Cubs, appearing in one game as a pinch runner. He played for them until 1968, before joining the Pittsburgh Pirates (1969-70), St. Louis Cardinals (1970), Boston Red Sox (1970) and Toronto Blue Jays (1977). His most productive season came in 1967 for Chicago, when he went 9-5 with a 3.08 ERA and 10 saves, all career-numbers. He also enjoyed a solid season with the 1969 Pirates, going 5-4 with a 3.85 ERA and 10 saves in a career-high 952⁄₃ innings pitched. After six years of absence, he pitched his last major season with the 1977 expansion Blue Jays.

In a six-season career, Hartenstein posted a 17-19 record with a 3.63 ERA and 23 saves in 187 relief appearances, including 88 games finished, a 1.52 strikeout-to-walk ratio (135-to-89), and 297.0 innings of work.

Following his playing retirement, Hartenstein coached for the Cleveland Indians (1979) and Milwaukee Brewers (1987-89). After he was fired by the Brewers, Hartenstein was hired to be a scout for the California Angels.

[ Source: Wikipedia ]