A problem with ESPN fantasy article: while money will come off the Yankee payroll by 2019, they spend every year for free agents. If they don't make the playoffs, and if the Mets compete, fans drift away. The current team has one starting player under 30; Gardner might be the next-youngest, and he's 32. Will the Yankees allow the team to crash for three or four seasons just to clear payroll?
The Yankees' best bullpen arm (and probably the best in the majors) is under 30. Their rotation features 4 guys under 30 (Tanaka, Pineda, Eovaldi, Warren & Nova shortly). By the beginning of 2017 they expect their 3 best hitting prospects (Judge, Bird & Jagielo) to be in the majors and playing roles in RF and 1B. I'm not sold on them being bad the next few years and then blowing big money in free agency. It is possible, but looking at their actions the last 2 years I don't see it. Things can change I guess.
They can easily clear payroll in the next 3 years by letting Sabathia, Rodriguez and Teixeira play out their contracts. That's over $70 million off the books a year right there. They're competing this year, and by the time Harper is a FA, all the big-time money will be off the books, surely replaced by some players (Pineda and Tanaka, Betances possibly, but relievers only get so much). I don't think it's some sure thing that they'll have to punt a few years to let the payroll clear. They've actually set themselves up nicely with their big-money deals the last 2-3 years, except for Beltran. Also the Mets are competing too and are not taking any Yankees fans away.
I think Harper has a good chance to come to New York but also think there is a very good chance he stays in DC.