James Luke Walker (born September 2, 1943) is an American former pitcher in Major League Baseball who played between 1965 and 1974 for the Pittsburgh Pirates (1965–66, 1968–73) and Detroit Tigers (1974).

His most productive season statistically came in 1970 with Pittsburgh, when he finished 15–6[1] (3–1, three saves in relief), while his 3.04 ERA, .714 winning percentage, and 7.1 hits per nine innings all ranked him third among National League pitchers.

[9] In a nine-season career, Walker posted a 45–47 record with a 3.65 ERA and 558 strikeouts in 243 appearances, including 100 starts, 16 complete games, seven shutouts, nine saves, and 8242⁄3 innings pitched.

[10] According to former Pirate great Steve Blass during one of Hank Aaron's last appearances at Pittsburgh's Three Rivers Stadium, Luke hit a rare single.

The home crowd erupted in cheers, which Aaron mistakenly assumed were for him, as is common even in road games when great players make their final plays.