Jimmy Rollins’ role has changed plenty over the last two seasons. With Chase Utley and Ryan Howard hurt to start the 2012 season, Rollins slid to the three-hole in the batting order in a lineup devoid of power. He has hit second in the order, too, from time to time. He’s been one of Phillies manager Charlie Manuel’s most reliable pieces throughout his Phils tenure. It’s been much of the same this year. Rollins, 34, has hit both second and third in the lineup, as well as his natural leadoff spot. But, in a second half (and next week, really) so crucial to the Phillies’ postseason hopes, Rollins is back in his leadoff spot. He will be there for the long run with Ben Revere injured. He has played 1,417 games of his 1,891 career contests. And if his history is any indication, he will be a big help. Howard is hurt again, and won’t be back for another month and a half at least. Utley is producing but, depending on whether the Phils are buyers or sellers, he might be wearing another uniform come August. Rollins is also a trade candidate, but he has another year left on his contract with a vesting option for 2015. He’s less attractive than Utley or Carlos Ruiz, whose contracts are over at year’s end. And should the Phillies want to stay buyers, as Phillies general manager Ruben Amaro Jr. has claimed, Rollins’ production will be key. Amaro said Sunday teams are inquiring about some of the Phils’ key pieces, should they become available. While he says he doesn’t want to be a seller, there will be plenty of suitors should the mindset change. “Many of the trades we’ve discussed, teams have asked for players that are on our major-league roster,” Amaro said. “It makes it difficult to subtract when we’re trying to add.” Rollins, a 14-year veteran, started slowly this season. He hit .258 in the first half with a .662 OPS, which one could label middling at best. Before his leadoff home run Saturday in New York, he hadn’t hit one in the stands in his previous 161 at-bats.