How many minutes did Jones play? If he was in on every defensive snap, I guess three tackles, a fumble recovery and a hurry or two is no big deal. If he only played half the snaps, it becomes a bigger deal.
He was up against Joe Thomas in the season-ending game last year and didn't seem overmatched.
And 38% is not half the snaps or bordering on half the snaps. It's 38% of the snaps.
Some people constantly root for failure.
So basically if he had played a whole game he would have had 8-9 tackles and was disruptive. I have watched him pick up his game in year 2. He isn't where the Steelers need him these things take time and I do like what I am seeing.