After another miserable outing, Humber will try again to change his fortunes in Sunday's series finale against one of his former clubs, the Kansas City Royals.Humber (1-2, 6.83 ERA) is 0-2 with a 13.50 ERA in three starts since recording the 21st perfect game in major league history April 21 in Seattle. He was tagged for eight runs over a season-low 2 1/3 innings Monday in Cleveland, getting charged with Chicago's 8-6 defeat."I'm frustrated," he said. "I'm doing my best. It's just the last two or three times out there, it's been rough. I'm definitely hoping for better results. I'm doing the best I can to make that happen, but right now it's kind of a grind."Humber was 2-1 with 4.15 ERA in eight appearances for the Royals in 2010, but wasn't nearly as effective in his only start against his former club Sept. 16 at Kauffman Stadium. Kansas City scored six runs in six innings against the right-hander, who managed to avoid the loss only after the White Sox rallied to tie the game en route to an eventual 7-6 loss.This time, Humber will face a Royals team that won 5-0 on Saturday after losing the series opener by the same score.The Royals (12-20) scored three runs in the first inning of Saturday's game with Billy Butler opening the scoring on an RBI single. Alcides Escobar added a run-scoring double in the eighth and Humberto Quintero brought him home on a single."The two tack-on runs in the eighth were huge," manager Ned Yost said.Chicago, which saw its three-game winning streak snapped, managed only three singles -- two by third baseman Brent Morel, back in the lineup for the first time since Tuesday after dealing with back soreness.The White Sox (16-18) will try to bounce back against Danny Duffy (2-2, 4.00), but they didn't have much luck versus the 23-year-old left-hander July 19. Duffy won his lone career start against Chicago, allowing two runs and five hits over seven innings.Duffy is now coming off his shortest outing of the season. He threw 102 pitches over 4 1/3 innings Tuesday against Boston, giving up four runs and seven hits. He avoided the loss when Butler hit a three-run homer in the eighth inning of Kansas City's 6-4 victory."I thought it was the worst outing of my year," Duffy told the Royals' official website. "I don't feel like I commanded any of my pitches the way I should have, but that being said, my teammates had my back the whole time."After being scratched Saturday because of a tight hamstring, third baseman Mike Moustakas might return to the Kansas City lineup. Moustakas went 2 for 3 off Humber last September, including a homer.