I think most people would see those stats and say below, but I think he's meeting if not exceeding. His "lack" of stats can be attributed to a lot of things. His production is certainly not where we expected it, as I think a lot of us thought he would have already eclipsed 100 tackles and 10 sacks by this point of the season /s. However looking at some of the stats...
Ohio State's defense has had.....
139 rushing attempts against (2.74 ypc)
124 passing attempts against, with only 56 completions (10 yds/completion, 4.5 yds/att)
You could assume at this point there have only been 195 opportunities to get a tackle (completions + rushing attempts), and that doesn't include guys running out of bounds etc.
The argument here is that while his number's aren't gaudy, he still leads the team in tackles, hasn't given up a rushing touchdown, is the leader of arguably the best defense in college football, and has hardly been tested by a team that likes to run the ball. His stats will come against wisco, sparty, scum, etc. I would bet a shit ton of money he has 10+ tackles against Wisconsin in two weeks because of the style of their offense.