I'm not overly worried at any position, but there are a few I would either like to see upgrades or at least think we need to see how things shake out. In no particular order ...
SAFETY - Woods appears to be improving, Heath isn't as strong as we would like, and Wilson provides some upgrade hope based on his play in preseason. If Wilson is that upgrade, we have no problem, but if not, we will have to accept some level of mediocrity.
TE - I think Jarwin can be very good as a receiver, and all 3 TEs have good hands, but it's unclear how the TE's will be used. Witten could take too much time away from Jarwin.
DE - D-Law is obviously not an issue, but the other side is uncertain. There are some options, with Quinn being the best hope for significant pass rush from that side, but he is suspended for a couple of games, and how much he has left in the tank remains to be seen.
LG - like with the RDE, there are options, none of which I think would be terrible, but it's uncertain if this position will be strong or just able to hold down the fort playing between 2 All-Pro players.