1. because essentially nobody expects Pillar to put up another 4 WAR season ever again.
2. because Soler is 23 and under contract until 2020.
3. because Soler was ranked (by BA) as the #12 prospect last year between Syndergaard and Sano and was one of the 3 best batters in the minors in 2014.
I love Pillar (can't help but root for him), but think I'd roll the dice - Soler was a beast in the minors. His K%'s were high, but not nearly as high as they were in what was a disappointing 2015 season. He also walked a fair share in the minors with BB% well over 10%. He has Puig/J.Upton potential with the bat (and hopefully without the baggage).
I think if you're given the perfect storm (as the article says, they are looking to upgrade and find a pure CFer) and can sell high on Pillar to land someone with the upside of Soler - you do it...especially when you have a replacement in Pompey...
Nevertheless - interesting discussion. I can only FAP to Travis's GF for so long.