SAN FRANCISCO -- Ron Santo and Pat Hughes are among the 75 candidates vying for the Baseball Hall of Fame's 2012 Ford C. Frick Award for excellence in baseball broadcasting.

This is Hughes' 16th season as WGN Radio's play-by-play announcer. Santo's last season as the team's analyst was 2010. The former Cubs third baseman, who died last December, began his broadcasting career in 1990 and teamed with Hughes for 15 seasons.

Fans can cast their votes for the Cubs' radio broadcasters at the Hall of Fame's Facebook page, www.facebook.com/baseballhall. This is the ninth consecutive year fans will select three of the 10 names on the ballot for the Frick Award.

Voting runs from Thursday through Sept. 30, and fans can cast votes once per day through September.

The Hall of Fame has trimmed the list of fan-eligible candidates to 75, with two representing every current big league team and 15 at-large selections. The selections were based on popularity, longevity and past voting results in the online fan balloting. Eligible candidates must have a minimum of 10 years of continuous Major League broadcast service with a ballclub, network or a combination of the two.

Results of the fan voting will be announced Oct. 5. The final 2012 Frick Award ballot will be comprised of the three fan selections, along with seven other candidates, determined by a Hall of Fame staff research team. The winner will be announced on Dec. 6 at the Winter Meetings.

Six Cubs prospects chosen for AFL

SAN FRANCISCO -- Pitchers Andrew Cashner and Chris Carpenter and outfielder Brett Jackson are among the Cubs' prospects who will play in the Arizona Fall League, which begins its 20th season on Oct. 4.

The trio will be joined on the Mesa Solar Sox team by pitcher Trey McNutt and infielders Junior Lake and DJ LeMahieu. Left-handed pitcher Jeff Beliveau is on the taxi squad as well.

The six-team AFL plays six days a week in six Cactus League stadiums in the Phoenix area, including HoHoKam Stadium in Mesa, Ariz., where the Solar Sox are based. Salt River Fields at Talking Stick has been added as the new home of the Rafters.

Cashner opened the season in the Cubs' rotation, but was placed on the disabled list after his first start April 5 because of a strained right rotator cuff. He has made three rehab starts at Double-A Tennessee and was to pitch for Triple-A Iowa this week before joining the Cubs in Chicago this weekend.

Carpenter was with the big league team, but has spent most of the season at Iowa, where he is 2-3 with one save and a 6.28 ERA in 20 games.

Jackson, the Cubs' No. 1 pick in the 2009 First-Year Player Draft, began the season at Tennessee and hit .256 in 67 games before he was promoted to Iowa in mid-July. He was batting .319 with nine homers and 13 doubles and six stolen bases in 43 games at Iowa.

LeMahieu, a second-round pick in 2009, began the year at Tennessee and batted .358 in 50 games and spent some time with the big league team before going to Iowa, where he hit .278 in 52 games with seven doubles and three homers.

Lake opened at Class A Daytona and then moved up to Tennessee at the start of June. He was batting .250 with nine doubles, one triple, six homers and 17 stolen bases in 61 games with the Smokies.

McNutt, a 32nd-round selection in 2009, was slowed by injuries this season. He was 5-5 with a 4.35 ERA in 22 games (21 starts) with Tennessee. In his last outing Monday against Jacksonville, he gave up one run over six innings and struck out five.

An 18th-round pick in 2008, Beliveau has a 1.66 ERA and a 5-1 record in 39 games with Tennessee.

Cubs muscling up in August

SAN FRANCISCO -- The Cubs have flipped on the power switch and lead the National League with the most home runs in August, hitting 38.

"Better late than never," Cubs manager Mike Quade said Tuesday. "I do tend to look back once in a while at how tough April and May can be for hitters, condition-wise, at home. I think back to some of the balls that [Carlos] Pena hit that would've gone in a lot of places."

Pena did not hit any home runs in April; he has 24 now.

"You just believe when you start the season the numbers guys put together over the years -- you may not get to where their average is but you surely don't think guys will be stuck in single digits, home run-wise," Quade said.

Extra bases

• Cubs first-round Draft pick Javier Baez will join Class A Boise on Tuesday to finish out the season. The ninth overall pick this June, Baez, 18, will be joined on the Hawks' roster by right-handed pitchers Michael Jensen, James Pugliese and Tony Zych. All three were Draft picks from this season and were in Mesa. Zych was a fourth-round pick out of the University of Louisville. Pugliese was an 18th-round selection from Mercer County Community College in New Jersey, and Jensen was the Cubs' 26th-round pick out of Hartnell Community College in California.

• Catcher Welington Castillo was placed on the disabled list with a hamstring injury for the second time. He spent two weeks on the DL with a similar injury, July 28-Aug. 11. In a corresponding move, catcher Mario Mercedes was called up from Boise.

The Cubs were expected to call up Castillo when rosters expand. Quade and interim general manager Randy Bush were to meet Friday in Chicago to consider their options.

• Bryan LaHair belted his 38th homer to set a single-season record at Triple-A Iowa Tuesday night. LaHair's blast in the sixth wasn't enough as Iowa lost, 7-3, to Nashville. LaHair now has passed Joe Hicks, who hit 37 homers for the Iowa team in 1984. LaHair came close to accomplishing the feat in the first inning, but settled for a double off the right-center field wall. In a pregame ceremony in Des Moines, LaHair was honored as the Iowa Cubs' 2011 MVP.