Isidoro León Becerra (January 4, 1911 – July 25, 2002) was a Major League Baseball pitcher who played for the Philadelphia Phillies in 1945. The 34-year-old rookie was a native of Cruces, Cuba.
León is one of many ballplayers who only appeared in the major leagues during World War II. He made his major league debut on June 21, 1945 in a home game against the Brooklyn Dodgers at Shibe Park. He was the starting and losing pitcher in a 9–2 defeat. Cy Buker was the winning pitcher. León's final big league appearance was on September 16. He was released by Philadelphia on February 26, 1946.
Season and career totals include 14 games pitched, 4 starts, 0 complete games, a 0–4 record with 4 games finished, 23 earned runs allowed in 38.2 innings, and an ERA of 5.35.
León died at the age of 91 in Miami, Florida.