Most Underrated Player: Los Angeles Chargers
I expect there to be a decline with Keenan Allen as he will either have Tyrod Taylor(big downgrade from Phillip Rivers) or Justin Herbert (not proven), Hunter Henry is injury prone and also Rivers loves to target his tight ends but he has left. Mike Williams didn't have a big arm quarterback throwing him the ball and he will continue not to have one, so his value is very low. Ekeler is efficiently based and gets a lot of receptions as Rivers loves to dump the ball down to his running backs. This leaves Justin Jackson.
Jackson may not seem like a great pick, but his stats from the previous season should be taken lightly. He was the third back behind Gordon and Ekeler and when Gordon went down they went with Ekeler as the workhorse rather than a committee between Ekeler and Jackson like they did with Gordon and Ekeler. He hasn't gotten the workload he deserves and needs to be fantasy relevant, however, he is efficient with the ball in his hands.
He is a great handcuff to Ekeler as well as he is currently the second running back behind Ekeler on the roster. Ekeler is a smaller running back and if the Chargers choose him to be the workhorse back, there is a high probability he will get injured at some point during the season. This would leave Jackson as the lead back.
I expect the Chargers to play more conservative this year which means more running the ball. Jackson could see around 10-12 carries with 1 reception a game which would warrant a late-round pick in regular PPR leagues.
With his draft value in the 14th round, Jackson is one of the most valuable handcuffs in the league, and with the improved offensive line in Los Angeles and Jackson's efficiency, he could be a flex option.