Designated hitter Travis Hafner faced a great deal of uncertainty when he surveyed his options during the off-season. Hafner, a former Cleveland Indians star, had never been a free agent. The freedom to choose his next destination was exciting, but he was also nervous about finding the right spot. Hafner, 35, was headed toward the twilight of his career, if he had not already reached it, and a successful final chapter required the best fit. About six teams were interested in him, but the Yankees always seemed the most appealing. First, the Yankees had a short right-field porch that would provide little obstacle for Hafner’s power. More important, the Yankees — who would be entering the season with several injured stars — provided opportunity. On Saturday, Hafner, who is second on the team in runs batted in, rescued the Yankees from a mostly uneven start from the ace C. C. Sabathia, who allowed four runs in eight innings. Hafner’s three-run homer in the fourth inning tied the score at 3-3, and his booming run-scoring triple in the seventh against Toronto’s Brett Cecil provided the winning margin in the Yankees’ 5-4 victory. For a stretch in the mid-2000s, Hafner was considered a premier power hitter in the American League. But then he sustained a variety of injuries that kept him off the field. Hafner has not had more than 400 plate appearances in a season since 2010. And he was not expected to reach that many plate appearances when the Yankees signed him to a one-year, $2 million contract. But Hafner has played so well that perhaps the plan will change. Ben Francisco was signed to be the primary designated hitter against left-handed starters, but he has struggled (he has a .103 average with no extra base hits), while Hafner has excelled. Hafner was given the start Saturday, even with the left-hander J. A. Happ on the mound. “I probably feel my swing is better suited to handle lefties this year,” Hafner said. Hafner’s above-average numbers against left-handers — he entered Saturday’s game with a career .804 on-base plus slugging percentage against them — might get him more at-bats against all pitchers. Both of Hafner’s extra-base hits on Saturday came against left-handers. Yankees Manager Joe Girardi said that he would consider giving Hefner more opportunities against left-handers.