He's worth a few shares. I think he's better than Mixon and if Mixon were to get hurt, he has huge upside in that offense. Texans gave Mixon the big deal, so I expect him to be the guy, but I don't think there's a large talent disparity between these two guys.
He was really, really bad last year and he got plenty of opportunities to not be bad. Ultimately he wasn't better than Devin Singletary, who is probably somewhat underrated. It's difficult to see an argument for his production this season that isn't predicated on a Mixon injury.
Even then I'm not sure he cracks the top five backup RBs that should be drafted in most leagues.
Jaylen Wright, Ray Davis, Trey Benson, Braelon Allen, Zach Charbonnet, Tank Bigsby, Trey Sermon, Algeier, Blake Corum, CEH, and that isn't even getting into the 1a/1b situations like Pittsburgh, Cincinnati, Tennessee, the Chargers, Washington or Detroit. Or situations like Carolina where we have to wonder what happens when Brooks comes back.
I might take Pierce over a couple of those guys (Bigsby and maybe Sermon) but, with little stand alone value I could easily see him go undrafted in a ton of leagues.