© 2014 MLB Advanced Media, L.P. All rights reserved.

5/24/2014 5:07 P.M. ET

As average rises, so could Pollock's spot in order

NEW YORK -- A.J. Pollock has been one of the better hitters for the D-backs of late. Entering Saturday's game, Pollock had recorded a hit in 12 of the previous 14 games. His .303 batting average was the second best in Saturday's lineup behind's Paul Goldschmidt's .315 average.

Yet manager Kirk Gibson said he is comfortable with keeping Pollock in the eighth spot of the order.

"I just chose to leave him down there for now," Gibson said. "Other guys have more experience. He works good down there. There's advantages to have him down there. If he gets one, and the lineup rolls over, he can influence what's going on at the top of the order."

If Pollock continues his success at the plate, Gibson said the lineup might be different in a week.

"I'm not sure we've quite found his permanent spot yet," Gibson said of Pollock. "Certainly, eighth is not that spot."

Spruill gets call to start Sunday's second game

NEW YORK -- The D-backs will add pitcher Zeke Spruill to their roster as the 26th man for Sunday's doubleheader against the Mets. Spruill will start the second game, following Game 1 starter Bronson Arroyo.

The move to summon Spruill from Triple-A Reno should allow the D-backs' rotation to stay intact for their next series with the Padres, which starts Monday. Manager Kirk Gibson said Spruill was a logical choice after Friday's game was postponed.

With the Reno Aces, Spruill has appeared in 12 games, going 2-1 with a 4.72 ERA in 34 1/3 innings pitched. Spruill, 24, was dominant in his last two starts for the Aces, as he pitched 13 1/3 combined scoreless innings.

"I think, all things considered, he's thrown the ball the best," Gibson said. "He's been here before and had some starts for us last year. I felt that was the right way to go. I'm looking forward to him throwing a good game for us."

The D-backs acquired Spruill from the Braves in the 2012 trade that sent Justin Upton and Chris Johnson to Atlanta.

Gibson mentioned that one of Spruill's best attributes is his poise. He does not expect Spruill to be fazed by trying to pitch the team to a victory while limiting the work of the bullpen.

Last year, Spruill started two games for D-backs, allowing 17 hits in 11 1/3 innings. Gibson said Spruill pitched well in Spring Training and that it was a strong possibility that he would help at some point during the season.

"The thing he didn't do last year was get lefties out," Gibson said. "So you kind of work on that and you might lose something on the other side of the ball. It will be interesting to see whether he improves in that area, because it's important that he does. He understands the importance of keeping the ball down."

Gibson still learning nuances of replay

NEW YORK -- Through 50 games, manager Kirk Gibson is still learning all the possibilities when it comes to replay challenges. Gibson and his staff have discussed what they think are plays they want to review and what the strategies are behind their decisions.

Most of the time this season, Gibson has just ran onto the field to give his staff a chance to see whether a close play is worth challenging. He has not challenged many.

The D-backs have challenged just four plays, the fewest in the Major Leagues. Gibson's record is 2-2.

"I think all four should have been changed," Gibson said.

Gibson said he feels the league's review system has worked pretty well. He does expect the system and its rules to be revised in the offseason. Before Friday's game, which was postponed and moved to Sunday, Gibson said he asked the umpiring crew how they want the managers to start the challenging process.

"The guys last night told me they would prefer us to come out and initiate the process," Gibson said. "When you come out right away, they understand that the process has been initiated. I think their attitude is, they are more open to making the right call."

Gibson said he pictured the command center to be a room full of officials reviewing plays in front of giant televisions, with each game that day being displayed on one the screens. He is actually pretty accurate. Gibson wanted to visit the replay center while the D-backs were in New York, but he decided he could not make the trip after Friday's rain delay lasted more than two hours.

Gibson instead had one of his video coordinators visit the center to learn more about the rules of what teams can and cannot challenge.

"My video guy said it was informative," Gibson said. "I think it was helpful to him. That's what he expressed to me."

D-backs focused on improving defensively

NEW YORK -- The D-backs, in their quest to improve, are putting an emphasis on defense, said first baseman Paul Goldschmidt. Arizona's fielding percentage this season is .980, which is the one of the lowest in the Major Leagues.

Goldschmidt, much like many of his teammates, knows he can do better. Through 50 games, Goldschmidt has almost as many errors this season (four) as he had all of last season (five) in 159 games.

"There's been some positives, but I think there's been some mistakes I've made," Goldschmidt said. "You're working on it daily. It might not even be an error. Maybe you throw to a different base or your positioning was a little bit off."

As a team, the D-backs have 37 errors, which ranks fifth in the Major Leagues. The Reds, who lead the Majors in the fielding percentage, have less than half that many errors (19) in comparison.

"I know we haven't played up to our potential," Goldschmit said. "We haven't done as good of a job as we need to do. For us to not be playing well this stage of the season has really taken everything -- and defense is a part of it."

Nate Taylor is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.