Lewis Bernard Krausse (June 12, 1912 – September 6, 1988) was an American pitcher and scout in Major League Baseball from Media, Pennsylvania. He pitched in parts of the 1931 and 1932 seasons for the Philadelphia Athletics. Krausse was used mostly as a relief pitcher by the Athletics, though four of his 23 appearances were starts. He compiled a lifetime record of 5–1.

A standout high school pitcher at Upper Darby High School, Krausse was signed by Philadelphia in 1931, becoming the youngest player in the American League (AL). After making three appearances in 1931, he pitched in 19 games in 1932. His final start of the season was a shutout, but a sore arm prevented Krausse from ever pitching in the major leagues again after that. He did play several more seasons of Minor League Baseball, most notably with the Elmira Pioneers, with whom he won two championships. Following his final season in 1946, he spent many years as a scout for the Philadelphia Phillies and the Athletics. His older son, Lew Jr., won 68 games in the major leagues.

Lewis Bernard Krausse was born on June 12, 1912, in Media, Pennsylvania. He attended Upper Darby High School, where he had a standout baseball career as a pitcher. A swift fastball was his primary pitch. The Philadelphia Athletics signed him and added him to the major league roster in 1931, making him the youngest player in the American League (AL) at the age of 18.

Krausse was seldom used by Philadelphia in 1931. He did not make his debut until the season's third month. Against the St. Louis Browns on June 11, he relieved Rube Walberg in the seventh inning after the latter had allowed six runs. Krausse pitched the final 2+1⁄3 innings of the game, allowing two runs himself as the Athletics lost 8–2.

Towards the end of the 1931 season, once Philadelphia had guaranteed itself a spot in the upcoming World Series, manager Connie Mack decided to rest star pitchers Walberg, Lefty Grove, and George Earnshaw. In the regular season's final games, he started the younger pitchers in their place. Making his first appearance since July and his first major league start, Krausse held the Boston Red Sox to four hits and one unearned run in a complete game, 7–1 victory on September 25.

In his three appearances in 1931, Krausse posted a 1–0 record and a 4.09 earned run average (ERA). He did not pitch in the World Series, which the Athletics lost in seven games to the St. Louis Cardinals.

After making $2,500 in 1931, Krausse was signed to a $3,000 contract in 1932. He pitched more frequently for the Athletics that season, mainly in relief, though he did start three games. On July 10, he started what Stephen V. Rice of the Society for American Baseball Research later called "one of the wildest and craziest games in baseball history" against the Cleveland Indians at League Park. Mack, with the team coming off three straight home doubleheaders and playing a single game series in Cleveland (necessitated by Pennsylvania's blue laws, which prohibited Sunday baseball) before returning home for another doubleheader, wished to save both train fare and the arms of his pitchers, taking only two pitchers with him, Krausse and veteran Eddie Rommel. After Krausse allowed four hits, including a three-run home run by Earl Averill in the first inning, Mack lost patience with his starter and replaced him on the mound for the second inning. Rommel pitched 17 innings in relief for the Athletics, who ultimately prevailed 18–17 in 18 innings.

Krausse only threw one shutout; it came in his final outing of the 1932 season. Facing the Red Sox in the second game of a doubleheader on September 2, and in only his second game since the end of July, Krausse held the team to six hits in a 15–0 victory. He finished his second season with a 4–1 record, a 4.58 ERA, 16 strikeouts, 24 walks, and 64 hits allowed in 57 innings pitched over 19 games. In 23 total games (four starts) over two seasons with the Athletics, Krausse had posted a 5–1 record, a 4.50 ERA, 17 strikeouts, 30 walks, and 70 hits in 68 innings.