The Mets called Powell up in July 1963. With the Mets behind 11-2 to the Los Angeles Dodgers, Powell made his major league debut in the ninth inning on July 13. Though he gave up two walks, Powell escaped his one inning of work without further damage. Despite this modest success, Powell was used strictly in "mop up duty" by Mets ManagerCasey Stengel through his first five appearances. In all five cases, the Mets were down a minimum of five runs when Powell was called upon to close out the game. Powell had a 1.88 ERA and sixteen strikeouts over 13 innings pitched when he was given his first opportunity to start on August 20 against the Philadelphia Phillies, who were coming off an eight game winning streak. Powell and Phillies starter Cal McLish engaged in a pitchers duel through the first seven innings before the Mets finally broke through for two runs in the eighth and two more in the ninth. Powell allowed four hits and four walks, while striking out six in a complete game shutout. After escaping a bases loaded jam in the sixth, Powell did not allow another base runner. It would turn out to be his only Major League win. In his next start on August 27, Powell was holding onto a 1-0 lead over the Pittsburgh Pirates when Donn Clendenon lined a pitch off Powell's cheek. He remained in the game through the end of the inning. Afterwards, he was taken to Presbyterian University Hospital for X-rays. The Pirates would come back to win upon his departure. His five innings of shutout ball against the Pirates lowered his season ERA to 0.95. From there, Powell pitched to a 5.06 ERA over the remainder of the season. He took his only career loss on September 5 against the St. Louis Cardinals. All told, he went 1-1 with a 2.72 ERA. He struck out 39, allowed 37 hits and 32 bases on balls in 49 innings pitched.
After the majors
Powell remained in the Mets' farm system through. Tendinitis limited him to just 42 innings, and cost him the entire season. He joined the Cincinnati Reds in, and seemed poised to return to the majors. In, he pitched 188 innings, and went 16-6 with a 2.54 ERA for the Southern League's Asheville Tourists. However, he was limited to just 45 innings in. Midway during the 1969 season, he was dealt to the Atlanta Braves for former major leagueinfielderMike de la Hoz. As a minor leaguer with the Braves, Powell went 1-7 with a 7.60 ERA through the season before retiring. Having left school to pitch for the Mets, he returned to the University of Pennsylvania to complete his degree in economics in 1966. In 1985, while visiting his son in the hospital, Powell was diagnosed with leukemia. He died later that year.