Chris Carter was drafted in the 15th round by the White Sox out of high school in Las Vegas in 2005. He hit .286/.350/.485 with 10 homers for Bristol in the Appy League in 2005 after signing. His defense at third base drew very mixed reviews, many projecting a move to first base eventually, and his plate discipline was shaky. I gave him a Grade C in the 2006 book, noting his power potential but that he had work to do.
Promoted to Great Falls in the Pioneer League in 2006, Carter hit .299/.398/.570. A brief trial in the Sally League went poorly due to excessive strikeouts, but he looked good in the Pioneer, doubling his walk rate compared to 2005. I raised him to Grade C+, noting his long-term power potential but being concerned about his batting average against better pitching. He was a first baseman by the end of this season.
Carter hit .291/.333/.532 with 25 homers, 67 walks, and 112 strikeouts in 467 at-bats for Kannapolis in the Sally League in 2007. As you know, he was traded to Arizona then on to Oakland over the winter. I gave him a Grade B+ in the 2008 book, due to the rapid improvement in his strike zone judgment.
2008 has been interesting. Carter hit .259/.361/.569 with 39 homers, 77 walks, and 156 strikeouts in 506 at-bats for Stockton in the California League. HIs strikeout rate shot way up compared to 2007, but he maintained a high walk rate, and obviously the power production is impressive. I'd still maintain him as a B+/B prospect heading into the off-season, but there are some issues here we need to examine.
First, at age 21 Carter is still quite young. He has "old player's skills"...power, plate discipline, high strikeouts, and players like that often peak early and then fade. But even accounting for that, he is likely 3-4 years away from his skill peak.
Two, defense. This looks like it is a big problem. Carter got in 41 games at third base this year, fielding .837 with a 1.88 range factor, obviously unacceptable. At first base he posted a .974 fielding percentage and made 10 errors in 40 games. In the outfield he got into 14 games in right field, with a .909 fielding percentage and a 0.71 range factor. If this doesn't spell born DH I don't know what does.
Third, strikeouts. I am not overly paranoid about strikeouts, especially if the player in question also draws walks. But 156 in 137 games is excessive, and at this point I have to very much wonder how much contact he will make against better pitching. The caveat here is that Carter HAS shown the ability to make adjustments before, developing much better place discipline at higher levels than he showed in rookie ball. And given his youth, I am reasonably confident in his ability to adjust.
All told, Carter is highly intiguing and one of the best power hitters in the minors. But I want to see what he does in Double-A before going higher than B+, and even a B+ assumes he will adjust and hit enough to be a DH in the majors. You can make a good case that he should be a plain B.