You know Still's story ... he fought alongside his daughter Leah while she battled cancer -- at the same time he was trying to earn a roster spot with the Cincinnati Bengals.

Together, Devon and Leah have raised millions of dollars for cancer research. In fact, Devon and Leah got an ESPY in 2015 -- the Jimmy V Perseverance Award.

But now, the 28-year-old seems to be at crossroads -- he hasn't caught on with a team since being waived by the Jets earlier this year ... so when we saw him in NYC we wanted to know what his future on the gridiron would be.

"I don't know. We'll find out in a couple of weeks. I'll make my decision about whether I'm gonna continue with my NFL career or move on with my next venture in life."

If Still decides to hang up his cleats ... he definitely has a future as a motivational speaker/fundraiser. Millions of people are rooting for him.

BTW -- We also asked Devon about the controversial hit Kiko Alonso put on Ravens QB Joe Flacco, and Still told us KA's wallet might get a little lighter soon.