Each of these players had a major-league career lasting exactly one game. (Larry Colton pitched 2 innings on 5/6/1968, while Dick Thoenen pitched 1 inning on 9/16/1967.) This is the rookie card for both players, and the only card for Thoenen. Surprisingly, Colton re-appears on a 1969 Phillies Rookies card.
Larry Colton was signed by the Phillies in 1964, and was a starting pitcher in their farm system for 5 seasons (1965-69), starting at least 25 games each season except for 1968. That season, he spent part of the time riding the bench in Philadelphia, along with some time on the DL.
At the time, it was reported that he "hurt his shoulder reaching for the telephone on his bedside table". Years later, it was revealed that he was injured in a bar fight, and it cost him his shot in the majors.
After the '69 season, he was sent to the Cubs to complete the Johnny Callison for Dick Selma and Oscar Gamble trade. Colton pitched the 1970 season for the Cubs AAA team, then was out of baseball until pitching the 1975 season for an unaffiliated class A team.
At one time, Colton was married to the daughter of movie star
Dick Thoenen was signed by the Phillies in 1963, and pitched for 7 seasons in their farm system. Although a starting pitcher for his first 3 seasons, he was converted to a reliever at the start of the 1966 season and worked out of the bullpen in double-A (1966), and triple-A (1966-69).
His cup of coffee was pitching the 4th inning in relief of starter Rick Wise. After giving up hits to the Dodgers' Bob Bailey and Luis Alcaraz, he retired Don Sutton, Nate Oliver, and Wes Parker in order.
I found this write-up about Dick Thoenen recently at the NJ Baseball blog. At the end of the blog post, there's a newspaper clipping listing the Phillies' September 1967 call-ups. Larry Bowa was among them, although he wouldn't get into a major-league game until April 1970.