PHOENIX -- The D-backs will watch Patrick Corbin closely in his Friday start against the Giants and decide after that if the young left-hander needs a break.
Corbin's last two starts have been subpar, and D-backs manager Kirk Gibson has been asked repeatedly whether fatigue is a factor.
"We'll have some special interest to see how Patrick throws," Gibson said. "If he struggles again, then we may look how to get him more rest. Whether it's inserting a sixth guy, or there's a couple of other ideas. For sure it's the one guy we don't want to push him; he's got a lot of innings right now, and we want to make sure we don't hurt him."
Corbin threw a career-high 186 1/3 innings last year between Double-A, Triple-A and the big leagues.
Corbin has thrown 182 2/3 innings this year, and in his last two starts he lasted a combined 10 1/3 innings with 13 earned runs.
"His velocity is maybe down a tick," Gibson said. "His changeup maybe not coming out with the same arm speed."
For his part, Corbin has said he does not feel any added fatigue and that rather it has been a matter of missing his spots and making poor pitches.
No. 3 prospect among latest D-backs callups
PHOENIX -- The D-backs promoted three more players Tuesday, one day after Triple-A Reno finished its season.
Shortstop Chris Owings had his contract selected and was added to the 40-man roster after Matt Reynolds was placed on the 60-day disabled list with a torn ulnar collateral ligament. Catcher Tuffy Gosewisch and third baseman Matt Davidson, both of whom had been with the team 10 days ago, were recalled.
Whether the D-backs will add players once Double-A Mobile's postseason run is over remains to be seen.
"Possible," D-backs manager Kirk Gibson said of more players coming up. "The guys we brought up now is pretty much who's going to be here. If we need to get a sixth starter, then some other guys may be in play."
Owings, rated the D-backs' No. 3 prospect by MLB.com, was recently named the Rookie of the Year and Most Valuable Player in the Pacific Coast League, and he was selected for the Futures Game during the All-Star festivities.
In 125 games for Reno, Owings hit .330 with 31 doubles, eight triples, 12 homers and 81 RBIs.
"Just playing baseball every day and getting out there and getting four or five [at-bats] every day was the biggest thing for me this year," Owings said. "I played a ton of games. I feel like just getting consistent ABs was the biggest thing and just learning from them and taking what I can from them. Trying to have better plate discipline and, I feel like, getting better counts and stuff like that helped me out."
Gibson did not say how much playing time Owings would get. The D-backs were already trying to find playing time for Didi Gregorius, Cliff Pennington and Willie Bloomquist at short before Owings joined the mix.
To improve Owings' versatility, the D-backs had him play some second base this year at Reno, but Gibson said he was not sure if he would use him there in the big leagues.
"I'm just going to come up here and learn," Owings said. "That's the biggest thing for me right now, is just get some experience up here and play another month of baseball is the biggest thing. If I get to play, just go from there."
Goldschmidt is University of Phoenix graduate
PHOENIX -- Paul Goldschmidt is now a college graduate.
The D-backs first baseman graduated from the University of Phoenix with a bachelor's of science degree in management after taking online classes over the past two years.
Goldschmidt completed three years at Texas State University before being drafted by the D-backs in 2009.
"I worked hard for three years, so I didn't want that all to be a waste," Goldschmidt said of why he decided to go back to school. "I love playing baseball, and I want to do it for as long as they'll let me, but you don't know -- that could end any day -- so you want to be prepared for whatever is coming forward in the future. A college degree can help you if you're trying to find a job or other stuff you're trying to do."
Goldschmidt learned of the University of Phoenix program while in Minor League camp with the D-backs after he saw some teammates taking courses. He began taking classes in April 2012, and other than a two-month break this past spring he has been going at it non-stop.
Goldschmidt could often be seen working at his laptop in front of his locker in the D-backs' clubhouse or on team charter flights during the season.
"Maybe," Goldschmidt said when asked if he might pursue a master's degree. "No immediate plans. Not right now for sure, definitely take a break for a while."
Part of the coursework included group projects done online, and occasionally one of his classmates would recognize his name.
"I had a few people that asked, 'Hey do you play for the Diamondbacks?'" Goldschmidt said. "Everyone was really nice and supportive."
Assistant hitting coach Turner Ward is also enrolled in the University of Phoenix, and Goldschmidt has shared his experience with other players like others had done to get him interested.
"It was nice to see other guys show me how convenient it is, because I didn't think it was going to be possible during the season," Goldschmidt said. "I talked to a lot of guys during Spring Training. I talked to a lot of the Minor League guys. I know guys were interested [in enrolling]."
Gibson allows frustration, for one night
PHOENIX -- D-backs manager Kirk Gibson is usually pretty good when it comes to keeping his emotions in check during his postgame press conferences. But after watching his team struggle at the plate Monday afternoon he let his frustration out.
"The offense on this homestand has not been good," Gibson said. "You'd have to ask them; I'm not sure why. Everybody isn't Cy Young, and sometimes you've got to beat Cy Young. You've got to figure out a way to do it. That part's disappointing."
By Tuesday's pregame session with reporters, Gibson was back to his old self.
"My comments yesterday, I think they were frustrated, and I was frustrated," Gibson said. "I think I was pretty clear about the fact that they still may beat you, but you need to maybe make them work a little differently; you have to have more confidence in waiting them out for better pitches, specifically the double plays."
Gibson was frustrated Monday by double plays hit into by Gerardo Parra and Wil Nieves.
"Parra pulled a first-pitch ground ball on the outside part of the plate," Gibson said. "That's what they wanted him to do. That's frustrating. Wil Nieves did the same. Sometimes you've just got to try and extend them, get some pitches on their arm and try and get them to start making mistakes. We got pressure on him, and they took him out right away. I was a little frustrated. I usually hold it in, but I'm good to go today."
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.