The Mountain View, Calif. native limited right-handers to a .190 average (53-179) and just one home run in 2013. Johnson entered the 2013 season rated by Baseball America as the No. 4 Prospect and possessing the Best Slider in the White Sox organization. He originally was selected in the second round of the 2011 First-Year Player Draft.
Semien (SIM-ee-in), 22, combined to hit .284 (147-518) with 32 doubles, six triples, 19 home runs, 66 RBI, 110 runs scored and 24 stolen bases over 137 games between Charlotte and Birmingham. He appeared in 73 games at shortstop, 41 at second base and 23 at third.
The 6-foot-1, 190-pound Semien was named Southern League Most Valuable Player after ranking among the league leaders in runs scored (1st, 90), on-base percentage (1st, .420), slugging percentage (2nd, .483), average (3rd, .290) and walks (3rd, 84). He reached base in 26 consecutive games with the Barons from June 29-July 28, batting .372 (35-94) with seven home runs, 18 RBI and 28 runs scored during the streak. Semien was promoted to Charlotte on July 31 and hit .264 (33-125) with four homers and 17 RBI.
The San Francisco native entered the 2013 season rated by Baseball America as the No. 14 Prospect in the Chicago system. Semien originally was selected in the sixth round of the 2011 First-Year Player Draft out of California-Berkeley, where he was teammates with Erik Johnson on a team that reached the 2011 College World Series.
Webb, 23, combined to make 42 appearances between Class A Winston-Salem, Birmingham and Charlotte this season, going 2-1 with a 1.87 ERA (13 ER/62.2 IP), 10 saves and 78 strikeouts. He limited opponents to a .194 average (45-232) and recorded an average of 11.2 strikeouts per 9.0 IP.
The 6-foot-3, 220-pound Webb began the season at Winston-Salem, where he threw 15.0 scoreless IP with 19 strikeouts over eight appearances. He recorded 19 strikeouts over 15.0 IP (10 games) at Birmingham and 21 in 20.1 IP (14 games) with Charlotte.
Webb, a native of Paducah, Ky., was acquired from Toronto with pitcher Myles Jaye on January 1, 2012 in exchange for right-hander Jason Frasor.
Gonzalez, 22, hit .254 (43-169) with two home runs and 20 RBI over 53 combined games between Birmingham and Charlotte this season. He threw out 37.0 percent (20-54) of attempted basestealers in 2013.
The 5-foot-11, 180-pound Gonzalez entered the season rated by Baseball America as the Best Defensive Catcher in the White Sox system. Gonzalez, a native of Porlamar Nueva Esparta, Venezuela originally was signed as a free agent on June 18, 2008.
Flowers, 27, hit .195 (50-256) with a career-high 10 home runs and 24 RBI over 84 games this season. He is scheduled to have season-ending surgery this week.
Omogrosso, 29, has been on the disabled list since June 29 after appearing in 12 games with the White Sox this season. He underwent season-ending surgery on August 4 to remove four loose bodies and shave down a bone spur in his right shoulder.
With the six roster moves, the White Sox 40-man roster is at 40.