Skaggs was called up from Triple-A Reno on Wednesday when the team needed an extra starter for a day-night doubleheader that day against the Marlins. The lefty tossed 6 2/3 innings of two-run ball to win his big league debut.
The way the schedule looks the rest of the way, the D-backs will not need more than five starters, and they already have Ian Kennedy, Trevor Cahill, Joe Saunders, Wade Miley and Patrick Corbin established in the rotation.
"I think the plan is to keep him here for a while," Towers said. "I can't tell you where he slots in. We're going to probably discuss [Friday], 'Do we go with a six-man rotation? Do we go with a five-man rotation? If we do go with five, then who's out?'"
One possible move could have to do with Saunders, who was reportedly placed on waivers this week. If he is claimed on waivers, the D-backs could trade him to the claiming team, or if he goes unclaimed, they would be able to deal him to any of the other 29 clubs.
If the D-backs do go with a six-man rotation, they have to decide whether to carry six or seven relievers in the bullpen.
"Do we go with a 13-man staff, which gives us one less position player until Sept. 1?" Towers said. "We'll talk about that [Friday]."
Teams can expand their rosters on Sept. 1, and whether the D-backs elect to call up a few players on that day or wait a little bit depends mainly on whether they're still in the postseason hunt at that time. If they are, they likely will take what they need from Reno, but if not, they will allow Reno's team to stay intact, since the Aces are in a playoff race themselves.
"We haven't really talked about the September callups yet," Towers said. "A lot depends on where we're at a week from now. If we're right in the thick of things, we'll probably load up. If we're not, then it depends on Reno. I care about Reno, but I care about the big league club, so if we're in it, I'll probably worry less about Reno and add extra bodies for our club."
One of those extra bodies could be right-hander Trevor Bauer, who struggled in an earlier stint in the Majors this summer.
Bauer has pitched better for Reno of late after being given a few starts off. During his time with the D-backs, he said he struggled with some groin issues that may have hampered his performance.
"It didn't do us any good or him any good if he wasn't [healthy]," Towers said. "I think the time off probably was good for him both physically and mentally."
Towers had better get used to making tough decisions when it comes to his pitching staff. In addition to Skaggs and Bauer, the D-backs also have prospects like David Holmberg and Archie Bradley at various stages in their development, as well as Daniel Hudson, who will be back from Tommy John surgery around the All-Star Break next year.
How to fit in quality pitchers is a dilemma that Towers is more than happy to face.
"It's nice to have young pitching, but looking forward, where do you put them all?" Towers said. "That will be the toughest thing. They're all at the higher levels and ready to contribute at the Major League level, which is nice, but you've only got so many spots in the rotation to fit them all in there."