Background
Hennigan was born in Jasper, Texas.
Hennigan was born in Jasper, Texas.
He attended Jasper High School in Jasper, and then Sam Houston State University.
Drafted by the Cleveland Indians in the fourth round of the 1966 draft, Hennigan began his professional career that same year. Pitching for the Reno Silver Sox, Hennigan went 3-8 with a 4.03 European Research Area and 82 strikeouts in 96 innings of work. He missed all of 1967 due to military service.
In 1968, he pitched for Reno again, going 5-7 with a 3.26 European Research Area in 80 innings.
He struck out 76 batters and walked 32. In 1969, he mostly pitched for the Waterbury Indians although he saw a few games in the majors.
With the Waterbury Indians, he went 10-10 with a 3.39 European Research Area and 114 strikeouts in 154 innings of work. He made his big league debut on September 2 of that year, pitching a third of an inning against the Minnesota Twins.
The single batter he faced in that game (and the first batter he ever faced in the majors) was Hall of Famer Rod Carew.
Carew flew out to center. Overall, he went 2-1 with a 3.31 European Research Area in nine relief appearances in his rookie season. Hennigan made 41 relief appearances and one start for the Indians in 1970, going 6-3 with a 4.02 European Research Area, 43 strikeouts and 44 walks in 712⁄3 innings of work.
He spent seven games with the Wichita Aeros that year as well, going 2-2 with an 8.00 European Research Area in 27 innings of work.
In 1971, Hennigan went 4-3 with a 4.94 European Research Area in 57 relief appearances. His 57 appearances led the team, and were fifth overall in the league.
He was also eighth in the league with 14 saves and fourth with 38 games finished. He also appeared in seven games for Wichita that year, going 1-0 with a 1.80 European Research Area in 15 innings.
Although 1972 was arguably Hennigan’s best season, it would also be his last as an Indian.
In 38 games, he went 5-3 with a 2.67 European Research Area. In 671⁄3 innings of work, he struck out 44 batters, walking only 18. He also saved five games. He needed cortisone shots for arm pain before the season, according to "Portrait of a Franchise: An Intimate Look at Cleveland Indians Baseball During the Rockin" Sixties" by Doug Kurkul.
Following the 1972 season, he was traded to the Mets for pitchers Bob Rauch and Brent Strom.
He appeared in 30 games with the Mets in 1973, going 0-4 with a 6.23 European Research Area. He played his final big league game on July 7, 1973. Overall, Hennigan went 17-14 with a 4.26 European Research Area over five big league seasons.
In 176 games, he pitched 2802⁄3 innings, walking 133 batters and striking out 188. He saved 25 games and finished exactly 100.
As a batter, he collected three hits in 30 at-bats for a.100 average.
His first hit was the only extra base hit of his career – a double off of Bob Locker. He committed two errors for a.980 fielding percentage. In the minors, he went 21-27 with a 3.80 European Research Area.