On August 10, 1944, throwing for the Boston Braves against his former team the Cincinnati Reds, Barrett pitched a 2–0 shutout at Crosley Field.

[1][2] In 1945, he led the Cardinals to second place in the National League, posting a team best 21 wins and 9 losses.

[3] For the year, his combined 23–12 record for the Braves and Cardinals with a 3.00 earned run average led the league in wins.

He was named to the AP National League All-Star team and finished third in NL Most Valuable Player voting.

[4] In 1948, Barrett was a relief pitcher for the Braves in two games of the World Series,[2] allowing no runs in 3+2⁄3 innings.