Delgado is 5-6 with a 3.96 ERA in 19 games (18 starts) this year after coming over from Atlanta in January in the trade that sent Justin Upton to the Braves.
One of the things that Delgado will need to figure out how to do in 2014 is cut down on the number of home runs he allows.
Though he's allowed fewer than one hit per inning pitched this year, Delgado has allowed a whopping 22 home runs in 111 1/3 innings.
"It's location," Towers said. "He's got great stuff. They're not missing his mistakes. His weapon is his changeup, and changeups -- as we saw with [Josh] Collmenter in L.A. -- it's the type of pitch that if you leave it up, damage could be had. And his breaking pitch is his third pitch. His homers are going to be getting too much of the plate, an elevated fastball or a changeup that's left up in the zone."
Whereas in the spring he struggled with his command, Delgado has not had any trouble with wildness in the Majors.
"I know when he starts, I'm confident," Towers said. "I like when he starts."
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.