By Tzvi Machlin It’s been two years since former Heisman Trophy winner and Pro Bowl quarterback Robert Griffin III stepped foot on an NFL field. But could he be open to coming back to the NFL? During a call with 106.7 The Fan in Washington today, RGIII said that he’s open to returning to the NFL – specifically to the Washington Commanders, his former team – for a couple of reasons: 1. He’s passionate about football, 2. He’d love the chance to mentor rookie quarterback Sam Howell. “To me, coming back to play is… if you have the opportunity to come in and mentor a young guy that I have a relat…