Andrew Miller is in the Arizona Fall League to work on some changes that Florida Marlins' coaches have made to his delivery, and while he's no longer a "prospect" in the strict sense of the word, it's a great use of the AFL by the parent club and elevates the overall quality of the league. Miller was strong on Saturday night, with an easier delivery that featured a higher slot (at or near three-quarters) and a more in-line landing (meaning he doesn't throw across his body the way he used to). The good news is that he was hitting 92-97 mph with some sink and showed a hard downward-breaking curveball -- better than the long, sweepy slider he threw from a low three-quarters slot before the changes. The bad news is that he didn't throw strikes, with two four-pitch walks in his two innings and another walk, finishing with 16 strikes thrown in 36 total pitches. The delivery is better, though, and he may just need time to get used to it.The rest of Keith's observations from a weekend in the Arizona Fall League -- including another young Texas Rangers pitcher to watch out for -- are available to ESPN Insiders.