Santo, who turned 23 a week ago, originally came to the Cubs in a trade last year that sent reliever Scott Williamson to San Diego. When he joined the organization, Santo was sent to Class-A Peoria and went 3-4 with a 4.11 ERA in seven appearances, including five starts.
This season, the right-hander is 4-3 with a 5.51 ERA in 49 innings, having split time between the rotation and the bullpen.
Santo may be a pitcher that has the talent to succeed, but coaches say he may also lack the consistency to live up to his potential.
"The big thing for Joel is consistently throwing strikes," Davis said. "We've seen a good breaking ball and good velocities, but it seems like he's always behind in the count. When you're behind, you have to throw a strike. If you throw strikes early, you have the benefit of being able to have the hitter guessing at what you're going to throw."
The slender 6-foot-3, 195-pound Santo throws a fastball in the mid-90s consistently but struggles most at controlling his secondary pitches.
He has walked 26 and struck out 27 this season.
"He definitely has a good arm and good movement on his fastball when he stays down in the zone," said Daytona pitching coach Rich Bombard. "He'll show you a good slider at times, and has a decent changeup. He's a young pitcher who just needs to pitch and improve his command. If he does that, his role will define itself down the road."
His coaches know what Santo has to improve on, and that he's happy to be back in the rotation.
Is that where he'll stay for good?
"I would say that at the minor league level, he's definitely a starter. But almost all starters have to go to the ‘pen in order to work themselves into the big leagues," Davis said. "Here at the minor league level, we're just trying to gain consistency."