It’s hard to gage Gibbs as a back in the nfl. If Detroit uses hime primary as a receiver, they should be ok. If they plan to utilize him as a runner, they wasted a pick.
While at GT, Gibbs averages as a runner were essentially the same as undrafted Mason. At Bama, his running numbers were a yard better than his GT numbers.
As a receiver, Gibbs far outshined Mason. It isn’t close. His receiving numbers at Bama were worse than his GT numbers, but there were more passing options at Bama.
In short, if detroit uses him primarily between the tackles, they would have been better off trading down for more picks. If they can get him in space so that he isn’t taking hits from LB and DL running down hill he could flip a few games for a few years.