Boston Red Sox After his military commitment, he re-joined the organization and began the season with the Red Sox. His first MLB victory came seven days later, a three-inning relief appearance against the Yankees in Boston. On August 5, in his sixth start, he pitched a seven-inning
complete game 2-1 victory over the
Cleveland Indians and their pitching star, future Hall of Famer
Bob Lemon. In total, he appeared in 39 games his first season, 14 as their starting pitcher, had a 9–8 win–loss record with three
saves, 98 strikeouts, and a 4.66 ERA in inning pitched. Following the season, Sisler was praised for his performance; he was selected by
Boston area
sportswriters as the "
Harry Agganis Award" winner, given annually to whom they voted as the top Boston Red Sox rookie, and was named to the 1956 "Rookie All-Star Team". On January 17, 1957, Sisler was re-signed by the Red Sox. The Red Sox expected Sisler to be a candidate for a
pitching rotation slot. He impressed his coaching staff during early spring practices, manager
Mike "Pinky" Higgins commented that Sisler "looks good; he's more mature and shows more confidence". When the regular season began, he was initially effective, winning three games against one defeat in his first four starts, including two complete game victories against the Yankees. At this point, he was 4–0 against the Yankees, earning him the moniker "Yankee Killer" from sportswriter Chester L. Smith of the
Pittsburgh Press. That was his last victory of the season, however, which he followed with two consecutive losses, pitching a total of four innings; he did not appear in another game until September 2. However, he finished the spring with two consecutive losses, including one to the
Pittsburgh Pirates, with whom his father was a special assistant to their
manager. He opened the regular season with a complete game victory against the Yankees on April 16. On May 2, he pitched his only career complete game
shutout, a 6–0 victory against the
Detroit Tigers and future Hall of Famer
Jim Bunning, improving his record to 3–1 for the season. Over the next two months, his average innings pitched declined during his starts, and on several occasions he entered the game in relief. He went winless from June 12 to August 9, when he defeated the Yankees. After what was considered a "disappointing" season, he did not impress with his first outing in spring training, giving up two hits and five
bases on balls in just two innings of work. Lack of pitching depth was a noted weakness for the Red Sox entering the season, with unpredictable youth and with hopes that Sisler could regain his previous level of success. Sisler opened the season slated as a relief pitcher with the idea that he would start in certain cases. In three relief appearances through April, he had a 6.75 ERA in inning pitched. Management decided that his performance along with a pitching staff that they considered inexperienced, Sisler and
Ted Lepcio were traded to the Detroit Tigers on May 2 for starting pitcher
Billy Hoeft.
Detroit Tigers Hoeft, who won 20 games for the Tigers in 1956, had continually under-performed since, and was noted for being in the manager's "doghouse"; however,
TimesDaily sportswriter Hap Halbrooks commented, "I can't see where they (Tigers) gained a thing in this transaction." The Tigers had lost 15 of their first 17 games of the season before the trade and decided that changes were needed. In addition to the Sisler trade they fired manager
Bill Norman and replaced him with
Jimmy Dykes. These moves initially proved effective, sparking a winning game streak, which began by defeating the Yankees in both games of a
doubleheader on May 3. Used exclusively in relief, Sisler pitched in 32 games for the Tigers, winning one game against three losses and collected seven saves, which was seventh most in the AL, and he did not record an error. The Tigers bullpen had won just nine games in 1959, but began 1960 with three straight victories, with Sisler pitching a scoreless two-inning appearance on April 22. His performance was considered a surprise, due to having a poor spring training. The draft occurred on December 14, 1960 and Sisler was selected by the Washington Senators with the fourth overall pick. New manager
Mickey Vernon defined Sisler's role with the team before the season began, designating him as their top relief pitcher. Sisler felt slighted by the Tigers, having been left unprotected by the team, and had considered retiring from baseball, but ultimately decided to sign with the Senators. Sisler was solid for much of the first half of the season, not allowing an
earned run until May 19, and by June 5 he had an ERA of 0.74, a 1–0 record with seven saves. It was at the point that his effectiveness declined rapidly, allowing runs to score in four of his next five appearances. Over the course of the next couple months, with his ERA steadily rising, his playing time was lessened, making just six appearances in the month of July, and five in August. Sisler, who was expected to be used as a relief pitcher, joined a Reds team that already had his brother
Dick, who was their first base
coach. His father, still with Pittsburgh, mentioned that he was relieved that his son did not play in a recent series between the Pirates and Reds, recalling how the mixed emotions he felt when his elder son, Dick, helped defeat the Dodgers in an important game in 1950 by hitting a
home run. The younger Sisler's season did not begin well; in his ten appearances by June 5, he allowed a run in all but three, and had a 4.97 ERA. On June 19, Sisler pitched a scoreless inning in victory against the Pirates, the first time George watched his son pitch as an opponent. Although Sisler's season was a disappointment, he completed the season well, allowing just one earned run over the course of his final eight games, as well as earning the victory on September 23, his final major league appearance. The Reds announced on February 9 that Sisler had signed for the 1963 season, although he did not make the Reds' NL club and was optioned to their
class-AAA team, the
San Diego Padres of the
Pacific Coast League (PCL). In 35 games pitched for the Padres, he started six, had a 6–9 record and a 3.40 ERA in 90 innings. ==Later life==