Polanco, who two days ago leapfrogged right-hander Jameson Taillon as No. 1 in Baseball America's ranking of top Pirates prospects, and Hanson were automatic choices to be protected.
The two pitchers are lower-profile and longer-term prospects, but with obvious upsides.
Rodriguez, a Dominican native who turned 22 a few days ago, was 9-8 with a 2.70 ERA in 26 starts between two Class A levels in 2013 (Bradenton and West Virginia). Rodriguez's fastball touched a new high of 96 mph this season, his fifth in the Pittsburgh organization.
Sadler, 23, a 25th-round Draft pick in 2010, satisfies the Bucs' penchant for ground-ball-inducing pitchers. With his key sinker ball, he featured a 56 percent ground-ball ratio this season, when he went 11-7 with a 3.31 ERA at Double-A Altoona before one late-season start in Indianapolis.
Polanco -- the Bucs' No. 2 prospect, according to MLB.com -- is clearly the offensive jewel in the Minors, currently tearing it up in the Dominican Republic Winter League after passing his first Double-A test. The 22-year-old played the first two months of 2013 at Bradenton then moved on to Altoona, where he batted .263 in 68 games, with six homers and 41 RBIs. An admirably disciplined hitter for a young player, Polanco had an equal number of 36 walks and strikeouts in 286 plate appearances with Altoona.
Playing for Escogido, Polanco had reached base in 23 of his first 24 Dominican Winter League games, through Tuesday.
Hanson remains listed as MLB.com's No. 3 Pirates prospect, with a lively bat and the athleticism to overcome the defensive blackouts that have marked his first four professional seasons. Hanson was charged with 32 errors in 127 games between Bradenton and Altoona last season, bringing his toll to 92 errors in 269 games at shortstop since 2011.
Hanson turned 22 last month, while playing for Scottsdale in the Arizona Fall League, where he batted .253 in 21 games -- with six more errors.
Players first signed at age 18 must be added to 40-man rosters within five seasons or they become eligible to be drafted by other organizations through the Rule 5 process. Players signed at 19 years or older have to be protected within four seasons. Clubs pay $50,000 to select a player in the Major League phase of 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.
That is, an international player or high school draftee signed in 2009, assuming they were 18 or under as of June 5 of that year, must be protected. A college player taken in the 2010 Draft is in the same boat.
After the quartet was added to the 40-man roster, the Pirates have 45 players who will be exposed to selection by other MLB organizations during the Rule 5 Draft on Dec. 12 at the Orlando, Fla., site of the Winter Meetings.