George Bernard Koslo was born on March 31, 1920 in Menasha, Wisconsin just outside of Milwaukee. The left hander was signed out of high school, making it to the big leagues in 1941 pitching in four games, posting a 1.90 ERA. He went 3-6 in 1942 before going off to serve in World War II from 1942 through 1945.
He returned to the Giants rotation three seasons later to win 14 games (6th most in the NL). He also lead the league in losses (19) hits (251) earned runs allowed (107) as well as starts (35) while overall posting a decent 3.63 ERA. Koslo was also a work horse pitching in 265 innings on the year, while pitching 200 plus innings in three of the next four seasons.
In 1947 he gave up Jackie Robinsons first career HR & served up 23 HRs to lead the league in that category. On the ’47 season he won 15 (15-10) posting a 4.39 ERA and once again allowed the most earned runs in the National league.
Two years later he had his best season, leading the league in ERA (2.50) going 11-14 while saving four games pitching 212 innings. He would post another losing record in 1950 but would then win ten or more games for the next four seasons. In the 1951 Giants pennant season, he was used mostly as a reliever, but had some big games as a starter as well. In his first start he pitched a two hit shutout in the Polo Grounds against The Cardinals. Two months later he threw another two hit shutout in St. Louis.
He won four games during the crucial September pennant race, pitching into the 9th innings three times in four starts. His 10 victories (10-9) tied him with George Spencer for fourth best on the staff. He had three saves & posted a 3.31 ERA making 39 appearances.
Post Season: He got the surprise start in Game #1 of the 1951 World Series and pitched a one run complete game victory. He struck out three & allowed seven hits beating Allie Reynolds. He came back in Game #6 and took the loss allowing 4 runs on 5 hits in 6 innings pitched in the final game.
After going 6-12 in 1953 his contract was purchased by the Baltimore Orioles where he pitched just three games. During that season he was sent to the Braves where he finished up his career near his hometown area of Milwaukee in 1955. In his final career appearance he gave up a game winning walk off HR. In his 12 season career he was 92-107 22 saves with a 3.68 ERA making 348 appearances.
Retirement: After baseball he worked for a publishing house in Menasha Wisconsin. He passed away there from unknown causes at age 55 in 1975.