CINCINNATI -- Prior to Friday's deadline to protect players from the Rule 5 Draft, the Reds added six to their 40-man roster.Added were infielders Neftali Soto, Didi Gregorius, Donald Lutz and Henry Rodriguez and right-handed pitchers Kyle Lotzkar and Pedro Villarreal. Cincinnati's 40-man roster is now full. Soto, a supplemental third-round pick in the 2007 First-Year Player Draft out of Puerto Rico and rated this month by Baseball America as the organization's best power hitter, spent most of the season at Double-A Carolina and finished at Triple-A Louisville. The 22-year-old first baseman led all Reds Minor Leaguers with 31 homers while batting .278 with 80 RBIs and a .333 on-base percentage. Gregorius, a 21-year-old shortstop from the Netherlands, endured a late start to his 2011 season because of a kidney ailment but batted .289 with seven home runs and 44 RBIs in 89 games combined with Class A Advanced Bakersfield and Carolina. Baseball America rated him as having the organization's best infield defense and best infield arm. Lutz, a 22-year-old left-handed-hitting first baseman and outfielder, batted .301 with a .358 on-base percentage, 20 homers and 75 RBIs in 123 games for Class A Dayton this past season. He was originally signed as a free agent out of Germany in 2007. Rodriguez, a 21-year-old Venezuelan who plays shortstop, second base and third base, split last season at Bakersfield and Carolina. He batted a combined .320 with a .372 OBP, 13 homers and 81 RBIs. Lotzkar, a 22-year-old starter who was a supplemental first-round Draft pick by Cincinnati in 2007, spent all of this past season at Dayton. A native of British Columbia, he was 3-2 with a 4.32 ERA in 14 starts. He walked 25 and struck out 72 in 66 2/3 innings. Villarreal, a seventh-round Draft pick in 2008 out of Howard College, was 11-7 with a 4.39 ERA at Bakersfield and Carolina. He walked 28 and struck out 109 over 149 2/3 innings. The Major League Baseball deadline to protect players is Friday at 11:59 p.m. ET. Players first signed at age 18 have to be added to 40-man rosters within five years or clubs risk exposing them to other organizations that could pluck them through the Rule 5 process. Players signed at 19 or older have to be protected within four years. Clubs pay $50,000 to select a player in the Rule 5 Draft, to be held on Dec. 8 at the conclusion of the Winter Meetings in Dallas. 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.