SAN DIEGO — He had just hit a baseball 434 feet off the brick warehouse in left field at Petco Park, so Trea Turner wanted another look. Once everyone in the Phillies dugout had congratulated him, Turner found an iPad. He replayed the swing.He smiled.“It was kind of funny,” Turner said after Tuesday night’s 4-3 win over the San Diego Padres. “That was what I worked on all day. Then you go in the game and it clicks. It happens. It was nice to have that immediate reassurance.”The Phillies are desperate to see their $300 million shortstop emerge from the fog of the first two months. There might be others more critical to reviving this season — the Phillies are back over .500 after Tuesday’s win — but Turner is undeniably important. Interim manager Don Mattingly texted Turner and Kyle Schwarber on Monday night to tell them he was making a change. Schwarber would bat first in Tuesday’s game. Turner was bumped to second.He homered. He singled. He also could not cleanly field a ball up the middle with two outs in the fourth, prolonging the inning and giving Manny Machado a chance to smash a two-run homer off Aaron Nola. A few steps forward, one step back. This entire thing has been difficult for Turner, who at times looks like someone trying to atone for a horrendous beginning to his season with one swing. It will not happen like that.So, at least, this was something.“Obviously,” Mattingly said, “getting him going would be huge for us.”