From the moment their names start emerging in late summer, attention is primarily paid to the "top prospects" chosen to play in the Arizona Fall League -- the first-rounders, the blue-chippers, the players who finished the season with a taste of the Majors and are fully aware that there's more to come. In short, the crème de la Minor League crème.
And to a large extent, that's how it should be. After all, the AFL, now in its 16th year, is known as a "finishing school" for top prospects as they hone their skills in preparation for the big leagues.
But by the end of the six-week schedule, a handful of players emerge and exceed all expectations with dominant numbers. Of course, you can't really call them "off the radar," since their organizations clearly hold them in high esteem by sending them to the AFL in the first place, but their performances qualify as unexpected nonetheless.
Here's a look at 10 players who've opened some eyes and raised their status even further with outstanding 2007 AFL campaigns:
Jake Arrieta, RHP, Orioles: His performance would not be all that surprising given his pre-draft status, but to make his pro debut on the AFL stage and perform the way he has is nothing short of amazing. Baltimore's fifth-round pick this spring out of Texas Christian signed too late to play during the regular season, but all he's done this fall is pitch 14 scoreless innings over 12 relief appearances for the first-place Phoenix Desert Dogs. The 6-foot-4, 225-pounder has struck out 15 and walked six while limiting hitters to a .133 average. At 21, he's also impressed AFL coaches with his fearless and calm demeanor on the mound. He went 4-0 with an 0.27 ERA for Team USA last summer.
Yung Chi Chen, 2B, Mariners: One of Seattle's top infield prospects, Chen represented Taiwan in both the 2006 Futures Game and the World Baseball Classic. But he underwent shoulder surgery just five games into his first Triple-A campaign, so there were questions about how much of the rust he'd be able to shake off when he returned to the field in the AFL. Answer: all of it. Chen, now 24, has battled for the league's batting crown right down to the wire, hitting .357 in 16 games for the Peoria Javelinas. His .456 on-base average ranks third in the league.
Brett Gardner, OF, Yankees: Gardner's name isn't often bandied about when people talk about the Yankees' top prospects, but it should be. A third-round pick in 2005, he leads the AFL with 15 steals (caught once), ranks second in hits and runs scored and is batting an impressive .333 for the Javelinas. His work ethic and intense style of play also has earned him Peoria's nomination for the Dernell Stenson Award for leadership. Gardner stole 39 bases between Double-A Trenton and Triple-A Scranton/Wilkes-Barre in 2007 after swiping 56 bags the year before. The highest drafted player in the history of the College of Charleston, he led that school to its first-ever NCAA Tournament appearances in 2004 and 2005.
Matt Harrison, LHP, Rangers: The 22-year-old southpaw joined the Texas organization from Atlanta in the deal for Mark Teixeira, but went on the disabled list with a sore shoulder just days before the trade. The Braves' third-round pick in 2003, he posted a 3.39 ERA in 20 starts for Double-A Mississippi and was a starting pitcher in the Southern League All-Star Game before being sidelined. In his first action for the Rangers organization, Harrison is 5-0 with a 1.23 ERA in six starts with the Surprise Rafters. He has 14 strikeouts in 22 innings and has limited AFL hitters to a .160 average. This is the year he must be added to the 40-man roster or else be subjected to the Rule 5 Draft. This performance would seem to make him a lock for the Rangers' protected roster.
Marc Maddox, 2B, Royals: A ninth-round pick in 2006 out of Southern Mississippi, Maddox was the Royals' Class A submission to the AFL to get him some experience facing a higher level of pitching, and he certainly has risen to the task. The Rafters' Stenson Award nominee has flirted with the .400 mark all fall, and his .388 average and .447 on-base percentage rank fourth in the league. He began 2007 at Class A Burlington and hit .301 in his first month, then moved up to Class A Advanced Wilmington and batted .259 in 101 games. He combined for 61 RBIs and 14 steals between the two stops. In his pro debut at short-season Idaho Falls in 2006, he hit .336 with 40 RBIs.
Juan Miranda, 1B, Yankees: The Cuban-born slugger who signed with the Yankees for a $2 million bonus is not a sleeper per se, though he did miss a significant chunk of playing time in 2005-06 waiting for his citizenship paperwork to be completed. A teammate of White Sox pitcher Jose Contreras on the Cuban National Team, Miranda, listed at 24, left his home country in early 2005 but was not able to play stateside until this past season. His performance in 2007 was inconsistent, as one might expect, but there were flashes of the power that made him so attractive to the Bombers. He combined to hit .265 with 16 homers and 96 RBIs between Class A Advanced Tampa and Double-A Trenton. He's hitting .295 with five homers and 17 RBIs in 22 games for the Javelinas and has shown power to all fields.
Sergio Romo, RHP, Giants: San Francisco's lone Class A entry for the AFL, Romo was off-the-charts impressive in relief at San Jose in 2007. He posted a 1.36 ERA in 41 games, striking out 106 and walking just 15 over 66 innings. A 28th-round pick in 2005 out of Mesa State, he posted a 7-1 record and 2.75 ERA at short-season Salem-Keizer that summer as a starter and a 10-2 record and 2.53 ERA at Class A Augusta in 2006 in both starting and relief roles. So how is he performing against higher-level hitters? The results are very positive, as his 0.75 ERA in eight games for the Scottsdale Scorpions shows. He's walked three and fanned 13 in 12 innings of work.
Scott Sizemore, SS, Tigers: Sizemore didn't join the Peoria Saguaros until mid-October as a replacement for shortstop Michael Hollimon, who left the club to join Team USA, but his numbers have equaled or exceeded most players' full-season output. He's hitting .386 with two homers and 14 RBIs in 17 games to go with a .583 slugging percentage. He played second base this summer at Class A West Michigan, forming a double-play combo with high-ceiling prospect Audy Ciriaco and hitting .265 with four homers, 48 RBIs, 33 doubles and 16 steals in 125 games. Drafted out of Virginia Commonwealth in 2006, he was the starting shortstop at Oneonta in his debut season and hit .327 to earn New York-Penn League All-Star honors.
Caleb Stewart, OF, Mets: Would anyone have predicted the Mets farmhand would be near the top of the AFL home-run race? And do it in just nine games? The former Kentucky Wildcat, who once went a school-record 7-for-7 in one game, missed more than two weeks with injury, but in his brief time he's hit .313 with five homers for Scottsdale. He batted .252 at Double-A Binghamton in 2007, slowed in the second half by a strained oblique suffered when trying to go deep in the Eastern League All-Star Game Home Run Derby. Ironically, the winner of that derby, Toronto's Sergio Santos, is his teammate on the Scorpions.
Corey Wimberly, 2B, Rockies: Providing more bang per square inch than anyone in the league, the 5-foot-8 switch-hitter is batting an eye-popping .392 for the Javelinas. A sixth-round pick in 2005 out of Alcorn State, Wimberly had been slowed by injuries, which have kept him from playing more than 100 games in a season thus far, but when he's active, he's running. He hit .325 with 50 steals in 87 games at Class A Advanced Modesto in 2006 and .268 with 36 steals in 92 games at Double-A Tulsa this season.
Lisa Winston is a reporter for MLB.com. This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.