The co-op league, which boasts about being the "finishing school for elite prospects," is where Guerra demonstrated a year ago to new manager Don Mattingly that he could close out games. Although he opened the season at Double-A Chattanooga, Guerra was soon saving wins for Mattingly in Los Angeles. Scott Elbert and Jerry Sands also made an impression on Mattingly in the AFL.
This year, the Dodgers have eight prospects in action for the Salt River Rafters, a club that also features prospects from Arizona, Detroit, Houston and Colorado. They are:
Steven Ames, 23, RHP, a 17th-round pick in 2009: He split time between Class A-Advanced Rancho Cucamonga and Double-A in 2011, with a 2.06 composite ERA in relief. Ames caught Mattingly's eye in the AFL last year, but gave up too many homers after his second-half promotion this summer.
Alex Castellanos, 25, OF, 10th-round pick in 2008 by St. Louis: Acquired in the Rafael Furcal trade, Castellanos is already off to a hot start, with three homers in seven games. Mattingly said Castellanos might be tried at second base after playing primarily in right field, although he started his pro career as an infielder. As a hitter, his 23 homers and 102 runs scored this year have management intrigued. He was the Texas League runner-up in batting (.319) and slugging (.562).
Gorman "Griff" Erickson, 23, C, 15th-round pick in 2006: Erickson was invited to last winter's development camp, so the Dodgers already liked him. But he added switch-hitting power to his game in 2011, while splitting time between Rancho Cucamonga and Chattanooga. His father, Gorman Erickson, was an outfielder in the Twins' organization in the early 1970s.
Stephen Fife, 25, RHP, third-round pick in 2008: Not the key player in the Trayvon Robinson deal (that was Tim Federowicz), he hasn't lived up to his Draft status coming off two full seasons as a Double-A starter. The AFL games will allow management to determine where Fife fits. He played in the 1999 Little League World Series.
Jake Lemmerman, 22, SS, fifth-round pick in 2010: Lemmerman had a typical struggle after his promotion from Rancho Cucamonga to Chattanooga, and already has had a shaky start in Arizona, with four errors the first week. Ultimately, with Dee Gordon at short, Lemmerman could move to second, although he hasn't played there as a pro.
Kyle Russell, 25, OF, third-round pick in 2008: Russell had another typical boom-or-bust season, with 20 homers and 154 strikeouts in 432 at-bats between Chattanooga and Triple-A Albuquerque, while his average slipped. As a college player, he hasn't shown the offensive improvement the club had hoped for. He's on the taxi squad, so he'll only play twice a week.
Cole St. Clair, 25, LHP, seventh-round pick in 2008: Cole projects as a situational left-hander. And with Hong-Chih Kuo's uncertain future, he could sneak onto the big league club next year to go with Elbert. A good showing in the AFL won't hurt that cause.
Josh Wall, 24, RHP, second-round pick in 2005: Wall was re-signed as a six-year free agent, and is coming off his first season as a reborn reliever, after six years as a struggling starter. Maybe he'll turn into a Joel Hanrahan that didn't get away.
Angelo Songco, who had a breakout season in 2012 after moving from the outfield to first base, was originally headed to the AFL, but instead will remain in the instructional league.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.