Oy.
There's a lot of egregious misinterpretation of stats going on in this thread, most of it involving people thinking they can read more into the tackle stat than you can. A few points to set people straight:
A Strong Safety leading a team in tackles is not necessarily a bad thing.
It's only a red flag if the team in question is one the the Tampa-2 type teams that play almost exclusively in 2-deep coverage shells. The Pats are not one of these teams. If a team plays a lot of cover-3, as the Pats do, with corners and a FS back and the SS up closer to the line, the Strong Safety will generally rack up tackles. Assisted tackles will be very common, as he'll often be the second guy to close on a player that a LB has engaged. Jerod Mayo, it should be noted, leads the team in solo tackles.
Also, a player's tackle totals doesn't tell you anything about how washed up he is.
The tackle stat is borderline useless. It tells you too little, and depends on too much. What use is a defensive stat that doesn't differentiate between a tackle made in which the ballcarrier was dropped like a sack of bricks and one in which the ballcarrier dragged the defender 12 yards before going down? What use is a stat that doesn't tell you whether a tackle is occurring because the LB's gap discipline is funneling plays into the SS's wheelhouse, or whether they're occurring because RBs are breaking into the open field?
Furthermore, tackle stats as compared to players on other teams are influenced by a whole bunch of outside factors. Teams with poor offenses tend to log more defensive snaps. Teams that run well, and frequently, tend to log fewer defensive snaps, as games end up having fewer possessions. Also, each stadium's stat recording crew has slightly different criteria for what counts as an assisted tackle -- some are generous, some are stingy. (And one team, last year, awarded a player more assisted tackles than the number of snaps he was on the field for. Whoops.)
And finally, Even if you COULD read as much into tackle stats as many of you are trying to, you really shouldn't try to do it after the third game of the season. At this point, there isn't a large enough sample size to put much stock in ANY stat.
All you can really gather from Rodney's tackle totals are that he's not being subbed out that much.