Most often, though, it's a matter of a player who has benefitted from the small sample of a college season (often less than one-third of a major league season) to post numbers that are essentially out of line with his ability. When combined with a modest increase in ability, these sample size issues can result in apparent improvement that it utterly awe-inspiring.
It's impossible to say, for each player in this survey, what the reasons are for their breakouts. It's interesting to speculate, though.
Hitters
Ryan Jones, East Carolina
The best power hitter, bar none, in the NCAA in 2004. Jones's power numbers are awe-inspiring, well ahead of any other player on a park-adjusted basis, and what's more he graded out (as of May 16) as the best overall hitter (by offensive winning percentage) as well.
But prior to 2004, there was no reason whatsoever to suspect that Jones was even a special player, much less the best hitter in the NCAA.
2004 : .406/.507/.891, .889 OWP, 45.0 xRAA
2003 : .264/.336/.370, .443 OWP, -3.7 xRAA
2002 : .260/.370/.327, .465 OWP, -2.4 xRAA
That's improvement. How incredible is it for a player to improve his slugging percentage by 521 points in a single season? Jones is an interesting player, a very small (5-7, 177) player and a centerfielder. His 2001 was similar : he had hit .279 with one home run. Has he changed his approach at the plate? He must have, to account for the massive increase in slugging ability.
I don't know what to make of Ryan Jones, so here's a picture of a cuttlefish.
Jed Lowrie, Stanford
A sophomore, Lowrie is the man competing with Jones for the title of Hitter Of The Year. As of May 16, he was slightly ahead of Jones in xRAA, slightly behind in OWP. He, too, has made an extraordinary improvement: after displaying very little power in his first year, Lowrie has suddenly become one of the best power hitters in the NCAA and flashes a .412 average to boot. As a middle infielder (playing both short and second) on one of the very best teams in the country, he is almost certainly the Most Valuable Player in the NCAA.
As Stanford associate coach Dean Stotz recently told Baseball America, "he's proof to anybody who plays baseball in high school that's not on a top 50 list that you can still make it." Still make it to be the very best player in the country, yeah.
2004 : .412/.512/.794, .887 OWP, 45.2 xRAA
2003 : .292/.349/.349, .465 OWP, -2.1 xRAA
Matt Macri, Notre Dame
2004 : .363/.473/.663, .820 OWP, 31.8 xRAA
2003 : .294/.386/.467, .562 OWP, 4.7 xRAA
2002 : .206/.273/.294, .238 OWP, -5.6 xRAA
Macri was 16th among hitters in adjusted xRAA as of May 16th. This is a true breakout season for Macri; though he showed some steady improvement over his previous two seasons the third baseman has been impressive at the plate, after hitting well in the Cape Cod League and leading that tough circuit in walks. Macri is considered to have sufficient ability to make it as a third baseman in the pros.
Macri is a case of a player who is better than his freshman and sophomore stats. In Macri's case, the .206 average as a freshman was due to elbow problems that ended in him having Tommy John surgery. Much of his 2003 was spent at less than 100%. Only in 2004 has he been healthy; and as a consequence has shown the talent that made him first-round material coming out of high school.
Caleb Moore, East Tennessee State
2004 : .478/.535/.783, .843 OWP, 30.0 xRAA
2003 : .234/.307/.370, .300 OWP, -11.3 xRAA
2002 : .216/.286/.304, .168 OWP, -14.5 xRAA
Moore, who is a junior catcher, has probably had the biggest turnaround of any hitter in the NCAA; even more so than Jones, because while Jones was at least close to an average player, Moore was a really terrible hitter during 2002 and 2003. He's more than doubled his batting average in 2004 compared to his previous career. He was the Southern Conference Player of the Year and currently ranks 26th in the NCAA on the xRAA list and if his production is for real (he's been hitting the ball solidly by all accounts) he'll be a fascinating pick. Opponents were 22-of-29 stealing against Moore this past season (and a true renaissance man, he put up a 1.29 ERA in seven innings on the mound).
Pitchers
Unlike with the hitters, none of the very best pitchers have been "Nowhere Men" this year. Certainly, none rank with Lowrie and Jones in terms of having exploded from nowhere. This tends to cohere with the observation that the list of top pitchers is more consistent year-on-year; and that the list of top pitchers contains more of the top prospects than the top hitters list. This is undoubtedly due to the alumnium bats; since they make it easier for hitters and tougher for pitchers, only the very best pitchers would have consistent success, while hitters who "use the metal" can rise to the top. This is purely anecdotal, but it's an interesting thought.
In a recent study at Baseball Prospectus, college stats god Boyd Nation showed a positive (if not particularly strong) correlation for hitters between adjusted college performance and performance in low A ball and rookie ball. (A correlation about the same as the correlation between low A and high A performance.) It would be interesting to see if that correlation for pitchers was stronger, which would help to confirm this analysis.
On to the pitchers!
Matt Fox, Central Florida
(no xR data available for 2002)
2004 : 89 IP, 2.02 ERA, 42.8 xRSAA, 292 xRA+
2003 : 45 IP, 6.60 ERA, -1.9 xRSAA, 97 xRA+
2002 : 7.1 IP, 4.91 ERA, 0.6 xRSAA, 111 xRA+
Just a huge improvement. Fox walked 27 men in his 45 innings in 2003, and was pretty run-unlucky, but in 2004 he's cranked up his already-impressive strikeout rate and cut his walk rate in half and his hits by over 30%.
Casey Janssen, UCLA
(No xR data available for 2003)
2004 : 92.2 IP, 3.69 ERA, 45.3 xRSAA, 249 xRA+
2003 : 72 IP, 5.88 ERA, 5.7 RSAA, 111 RA+
2002 : 44.1 IP, 4.06 ERA, 7.0 RSAA, 125 RA+
Janssen's an odd case; a pitcher whose srikeout numbers (from 9.1 to 8.1 this year) actually decreased as he improved. I don't have an explanation for Janssen, other than that he was probably run-unlucky in 2003. He certainly was hit-unlucky; despite those 9.1 strikeouts per nine innings, he gave up 93 hits in 72 IP, while in 2004 he surrendered 76 in 92.2.
Zach Jackson, Texas A&M
2004 : 92.1 IP, 3.02 ERA, 44.7 xRSAA, 253 xRA+
2003 : 112.2 IP, 4.31 ERA, 14.7 xRSAA, 141 xRA+
2002 : 83 IP, 4.77 ERA, 19.9 xRSAA, 157 xRA+
Jackson really didn't show any more improvement than a lot of other players not in this article, but I am including him as an example of what a transfer can do. Those first two seasons were spent at Louisville, and that 2003 is an example of a player stagnating in a situation that doesn't suit him. A move to College Station, and Jackson has become lights-out and a likely first-round pick.