In the 1952–1953 season, Fornieles posted a 12-5 record for Marianao while leading the Cuban League pitchers with a 2.33 ERA. He pitched 155 innings in 29 games, and earned the league's Rookie of the Year honors. During the 1956-1957 season, Fornieles went 11-7 with a 2.47 ERA in 29 pitching appearances, allowing only 115 hits in 142 innings of work. With a one-two punch in the rotation of Jim Bunning and Fornieles, Marianao defeated the defending champion Elefantes de Cienfuegos and their ace Camilo Pascual to win the title and represent Cuba in the 1957 Caribbean Series. In Game 4 of the Series on February 10, Fornieles hurled a three-hit, complete game 7–1 victory against the Leones del Caracas of Venezuela. After two days of rest, he started Game 10 on February 13, also against Venezuela. He did not record a decision, as Cuba scored three runs in the bottom of the ninth inning to win 5–4, and the Series title. Overall, Fornieles finished with a 1-0 record, a 2.81 ERA and 13 strikeouts in 16 innings. Fornieles returned to Cuba in the winter of 1957-1958 to play for Marianao. In a very solid effort, he went 11-6 with a 2.09 ERA and 90 strikeouts in 155 innings. Once more, the Tigres captured the Cuban League title and advanced to the 1958 Caribbean Series. Fornieles started the Opening Game of the Series on February 8, and he led his team to a 10–2 victory over the Industriales de Valencia of Venezuela. On February 11, again with two days of rest, Fornieles faced Venezuela in Game 7. But he struggled this time and Venezuela scored eight runs in the first two innings en route to an 8–1 victory. Nevertheless, Cuba won the Series with a 4–2 record to become the first team to win its third straight championship (fifth overall) in Caribbean Series history. Overall, Fornieles had a record of 2-1 with a 3.08 ERA in his four series appearances, all against Venezuela. Cuban Baseball League statistics