I'm not worried about his power, he has never been known to hit a lot of Home Runs, Speed is the biggest asset for him. Obviously you haven't seen any decrease in speed yet because he just turned 30.
Its going to hurt when it starts to though.
Carl hits a lot of triples. One-hundred five triples before the age of 30 is a lot of triples. When his speed goes, those triples turn into doubles. That’s not so bad, but Carl loses some value. He’s a great base stealer with an 82% success rate. When he loses a step, that might drop to 70%, which is near the break even point in terms of runs, so again he loses value. He receives a nice chunk of value from his defense. Again, a lost step makes that less valuable. I also suspect he beats out a lot of infield grounders for hits. Again, with a loss of a step, his batting average suffers. Since his BA is large percent of his OBP, that will suffer with it.