Quackenbush, a right-hander who turns 24 on Nov. 28, didn't allow a hit or a run in his first nine games in the Fall League. He finished with a 2.45 ERA in 11 appearances with 16 strikeouts and six saves. He then earned the save in the AFL title game.
"He's got size, he's a thick, durable guy with a fastball that runs 90 to 94 and probably sits about 92 mph. ... But the big thing is guys just don't see him. He has tremendous deception," Smith said. "It's invisible."
Quackenbush was 3-2 with a 0.94 ERA and 27 saves in 52 games during the regular season for Class A Lake Elsinore. An eighth-round pick in 2011 out of the University of South Florida, Quackenbush has a 0.81 ERA and 144 strikeouts in 99 2/3 professional innings.
"He's got an average curveball and changeup, and we've encouraged him to throw them more, but his answer is they just don't hit his fastball," Smith said. "I don't know how much more there is for him to prove. His numbers are crazy."
Quackenbush will begin the 2013 season at Double-A San Antonio but could move quickly if he continues to have the kind of success he's had in his first two professional seasons.
Stites, a right-hander, was a 17th-round Draft pick out of the University of Missouri in 2011. He spent the entire '12 season with Class A Fort Wayne, going 2-0 with a 0.74 ERA and 13 saves in 42 games. He had 60 strikeouts and allowed 25 hits in 48 2/3 innings.
Stites continued that success in the Fall League, posting a 3.21 ERA in 12 games with 15 strikeouts in 14 innings.
"He's just been very consistent from the day he put on a uniform," Smith said. "He's got three pitches for a short reliever, and he throws strikes. He's got good stuff and throws it over the plate. His fastball is good and the slider and changeup are also good. He just needs to use them a little more."
Stites has what Smith calls a "plus-plus fastball," a pitch that typically sits between 93 and 95 mph. He touched 99 mph during the regular season.
Stites, 22, was a strike-throwing machine for Fort Wayne. He walked all of three hitters this season and has issued just 11 walks in 83 professional innings. He missed the equivalent of three weeks with soreness in his right shoulder but was completely healthy by the end of the season.
"All of it seems to be resolved now," Stites said recently.
The Padres asked Stites to work more on his secondary pitches during the Arizona Fall League -- his slider and his changeup against left-handed batters.
"I'm here more for my off-speed stuff," he said.
There's a chance that Stites could make the jump to San Antonio, skipping over Lake Elsinore. But that decision will be based on how he fares during Spring Training.