Neil Walker - Wikipedia
Sources: Why the Pirates really put Gregory Polanco on outright waivers
Pirates part ways with longtime outfielder Gregory Polanco
David Dahl called up: What to expect and look for from the prospect - Purple Row
Gregory Polanco an exercise in 'what could have been' for Pirates - Bucs Dugout
MLB roundup: Kris Bryant whiffs 3 times in Cubs debut - The Boston Globe
Gregory Polanco: “The Walking Toolshed” - Pirates Prospects
2017 Organizational Review: Pittsburgh Pirates - 2080 Baseball
Get excited: Top Pirates prospect Gregory Polanco is making his debut tonight
What will the Pirates do next in right field after releasing Gregory Polanco? - The Athletic