Looking at this as a projection post it's really tough to grade things but for me it should be assumed that the additions via FA, the draft and growth by last years rookies should be reflected.
Quarterback B+ (pending other units improving and how OCs work)
Against what most of the media thinks I did not think Tua had a poor rookie season. He had 3 poor games out of 9 and he was not asked to do too much in his first game so the stats for that are negligible. I think that the negative narrative on Tua is that he was pulled in 2 games (which you really don't see on a rookie) and the fact that Herbert had a ground breaking season. If it was not for these things Tua would probably not be mentioned in a negative manner tbh cause he had a typical rookie year based on precedence. I think with improvement across receiving unit, running game and OL, Tua should see a significant jump. Additionally, we have to see how the OC tandem will work for the play calling, this is an experiment and hope it pans out. Bottom line Tua can't be his own blocker, can't catch his own passes and can't be our running back, hence need all the units to step up and support each other.
Offensive Line B
Last year the offensive line had some good games but also showed that they had severe issues. Off the top of my head the Broncos and Bills game were some of the worse I saw from that unit and both those games were losses.
I am being more hopeful that this season the rookies improve significantly and the FA/Draft additions push them to above mediocrity.
If the OL improves then the passing and run game improve, this area is very critical.
Wide Receiver/Tight End B+ (Pending other units improving and OC play calling)
I really feel that this unit should significantly improve with the players brought in FA and draft. I expect Waddle and Fuller to really help this unit out and hopefully less injuries than last year. Again improvement will be based on other units improving specifically QB and how OC play calling goes.
Running Back B- (pending other units improving)
I may be one of the few that feels that our RB group is better than what we've seen. I feel with improvements across receiving unit (extend the field), OL (better run blocking), tight end( better blocking) and play calling this unit should do well. We don't have the type of RB that's going to run 80yd TDs, but do we need that? not really.
Defensive Line B+
The addition of Phillips should improve this unit. Hopefully Phillips remains healthy throughout the season.
Linebackers B-
Didn't really address this in the draft, got Mckinney in FA. I am really not sure how much of an improvement there will be but I give them a low B for now.
Secondary A
Stronges unit and getting stronger. The vets have to play at their top and Noah needs to have significant improvement from year 1. I hope Holland is effective immediately and becomes the player we wanted Minkah to be.
Special Teams B
Jason Sanders is one of our best player in this unit, other than that I don't have too much knowledge here. Hoping for a solid B.