In this increasingly topsy-turvy baseball universe, you should turn your telescope around to get the best feel for how the Yankees will eventually reinforce their starting rotation. It used to be, forever plus a year, that the Yankees would brandish their dollars as their weapon of choice to pursue another World Series title. These 2018 Yankees, however, will punctuate a trend that began nearly 10 years ago and hit some speed bumps along the way before establishing rank: Their primary currency will be not dollars, but prospects. Which means that a July trade, fueled by prospects, remains more likely than a spring-training pouncing on the lingering free-agent starting pitchers, which would be fueled by dollars. Before he departed George M. Steinbrenner Field for the Yankees’ game in Clearwater, Aaron Boone met with the media Sunday morning and poured cold water on the simmering scuttlebutt the Yankees would wind up with an available free-agent arm like Jake Arrieta, Alex Cobb or Lance Lynn. “At this point, I don’t really see those guys as realistic options, but that’s also something I leave with [general manager Brian Cashman],” Boone said. “I know Cash is always kicking the tires and always looking for ways to improve the club and monitoring every situation, but as we sit here today, it’s my understanding that those guys aren’t really in play for us. I’d be surprised.” The Yankees have about $15 million to spend on their 2018 roster before hitting the $197 million luxury-tax threshold that they are determined to stay under to reset their tax rate for 2019. Maybe Cobb or Lynn could lower their asks below that range, and you’d think that some price point would entice the Yankees. It would have to pretty darn low, though, wouldn’t it? For if the Yankees went big now, they’d be pretty restricted come the July 31 non-waivers trade deadline.