The Arizona Fall League season is about 2/3rds over and several Cubs prospects continue to impress.
Leading the list is Starlin Castro. This kid is making a major push to make it to the big leagues in 2010. He is leading the AFL in hitting with a .424 average and made the AFL's All Star team, which was played last night, and went 2 for 3 in the game. He could soon surpass Josh Vitters as the Cubs top prospect (if he hasn't already). If he doesn't make the Cubs out of spring training, he could be up by early May (as a lot of teams like to defer service time to avoid "super two" status).
Josh Vitters has also had a nice run in the AFL, posting a .360 average in 50 AB's. He hasn't shown much power (0 HR's), but its good to see him continue his hot hitting into the fall.
Andrew Cashner continues to impress in the AFL as well. After a rough first start, in which he gave up 3 runs in 2 IP, he has settled down and pitched 11.2 innings while giving up only 1 run. Overall, he has a 2.64 ERA with 11 K's in 13.2 IP.
James Russell also bounced back from a poor first outing (2 ER in 2 IP) to pitch 8 straight scoreless innings. Overall he has a 1.80 ERA with 9 K's in 10 IP.
Blake Parker has excelled, but hasn't pitched too poorly and currently has a 4.00 ERA in 9 IP, with a 6/5 K/BB ratio.
John Gaub has been roughed up a bit (8 ER's in 7 IP), but does have 11 K's, so it hasn't been all bad. Still, he has to start fooling more hitters (11 hits allowed), if he is going to be successful.
Finally, Wellington Castillo played in only 4 games before leaving the league. While he hit .357 in 14 AB's, its not really enough to go on.
Overall, you cannot place to much emphasis on a player's performance (good or bad) during the AFL. However, for a player coming off a good minor league season (like Castro and Vitters), a strong performance in the AFL can improve their status even more and help accelerate the promotion to the majors.
Also, the big league club sometimes uses the AFL to get a player experience at a new position (such as Castro playing second), if they have a potential hole to fill on their major league roster.
Both of these things bode well for Castro. So, make sure you keep an eye on him in spring training.