McCool, who played the first five of his seasons with the Cincinnati Reds, appeared in 18 games for the Cardinals in 1970, all out of the bullpen, going 0-3 with a 6.23 earned run average in 21.2 innings of work.
The year before, he was one of the original San Diego Padres, going 3-5 with a 4.30 ERA over 54 games for the new Major League franchise in their inaugural season.
As stated earlier, the rest of his time on a Big League mound was spent with the Reds, having a couple of good years back-to-back, 1965 and 1966, when he saved 21 and 18 games respectively.
As a 19-year-old in 1965, he had a really good season when he went 6-5 with a 2.42 ERA with seven saves over 40 games, though he didn’t pick up a single Rookie of the Year vote, the award being won by Jim Lefebvre in a rather lackluster campaign (actually Joe Morgan should have won the award).
Overall, McCool finished his career with a record of 32-42, along with an ERA of 3.59 and 58 saves over 292 appearances and 528.1 innings of work.