Simon, who has a 1.41 ERA in 23 appearances this season, has two victories and a hold in his past four outings and hasn't allowed a run in any of his past seven games.
"Right now, every time I go out there, I just try to do the best I can and right now I feel really comfortable and I have to be ready for every situation they put me in," Simon said Saturday. "I try to put a zero on the board and win games."
Pitching in Friday's 3-0 Reds win over the Rockies, Simon replaced Bronson Arroyo and worked 1 1/3 scoreless innings with one hit. He was working on eight days of rest.
The 12th man in the bullpen when he was acquired just before Opening Day, Simon was used in only one winning game over his first 15 appearances of the season. In his last eight outings, the Reds have won in five of the games.
"He's elevated his game and his position since he's gotten here," Reds manager Dusty Baker said. "We're a team. Everybody has a job, a time, a place and situation."
Simon, who has pitched three innings twice this season, felt that staying sharp in between lengthy idle periods was his biggest challenge.
"It's really hard," Simon said. "I've never been in this situation before. I know the starters are doing good right now. And when they go seven or eight innings, I don't have a chance to go in. Everybody is doing a great job. I just have to adjust and handle it. Right now, I'm the long reliever."