SAN FRANCISCO -- The Giants added five Minor Leaguers to their 40-man roster Tuesday night, increasing the contingent to 35: right-handers Jake Dunning and Chris Heston, infielder Nick Noonan, outfielder Juan Perez and left-hander Edwin Escobar.

The moves protect the quintet from being plucked by other teams in the Rule 5 Draft, to be conducted Dec. 6 at the Winter Meetings in Nashville, Tenn.

Dunning, 24, finished 5-2 with a 4.10 ERA in 44 relief apppearances for Double-A Richmond this year. A 33rd-round selection by the Giants in the 2009 First-Year Player Draft, Dunning continued his ascent through the organization, having pitched for Class A San Jose in 2011 and Short-Season Class A Salem-Keizer in 2010.

Heston, 24, was named an Eastern League midseason and end-of-season All-Star while posting a 9-8 record with a 2.24 ERA in 25 starts for Richmond. Rated the organization's 17th-best prospect by MLB.com, Heston struck out 135 and walked only 40 in 148 2/3 innings.

Noonan, 23, had perhaps his strongest season in six years in the Giants' system. Formerly a second baseman, the left-handed-batting Noonan played primarily shortstop for Triple-A Fresno and hit .296 with nine homers and 62 RBIs in 129 games.

Perez, 26, led Richmond with a career-high .302 average in 126 games, to go with 10 home runs, 53 RBIs and 18 stolen bases in 33 attempts.

Escobar, 20, improved dramatically this year while going 7-8 with a 2.96 ERA in 22 starts for Class A Augusta. Opponents batted .241 against him, compared with .319 in 2011 when he pitched in the Arizona League and Augusta. Escobar recorded an enviable strikeout-to-walk ratio, striking out 122 and walking 32 in 130 2/3 innings with Augusta.

Major League Baseball's deadline to protect players was Tuesday at 8:59 p.m. PT. Players first signed at age 18 must be added to 40-man rosters within five years or they become eligible to be drafted by other organizations through the Rule 5 process. Players signed at 19 years old are to be protected within four years.

Clubs pay $50,000 to select a player in the Rule 5 Draft. If that player doesn't stay on the 25-man roster for the full season, he must be offered back to his former team for $25,000.