OAKLAND -- With the A's set to embark on a six-game, seven-day road trip to Arizona and Colorado after Thursday's series finale against the Rangers, the lack of a designated hitter in the National League parks means manager Bob Melvin has some lineup juggling to do.

Melvin's main problem lies in the outfield. He usually rotates Jonny Gomes, Seth Smith and Collin Cowgill through the DH and left-field spots, depending on matchups and who's swinging a hot bat.

"They're going to get their at-bats," Melvin said on Thursday. "It might just be one. As far as a pinch-hit [situation], I think that the fact that they do DH lends to being able to pinch hit. And as I told them for the Giants series for our advance meeting, from the fourth or fifth inning on, every one of you guys has to be ready for whatever."

Interleague games can present a challenge for managers, as they have to suddenly get used to a different style that they may not be used to. Having been in the NL before, though -- spending five years as the D-backs' manager from 2005-09 -- Melvin does have plenty of experience running a game without a DH. He said that should come in handy in Arizona.

"Now, you get used to doing it a certain way, and you have to start thinking a little differently and ahead of time, [saying], 'OK, look, remember, don't miss out on this,'" Melvin said. "And each and every inning during a National League game, I'll go to the card and say, 'OK, here are the variables that come up,' just to make sure that something doesn't slip by me. That doesn't mean something won't slip by me, but you try to be overly prepared for that."

Of course, this particular Interleague series against the D-backs is more interesting than most, given Melvin's stint in Arizona, when he led the team to the NL West title in 2007. The A's manager said he got some of those feelings out of the way last season, when Oakland faced off with the Diamondbacks at the Coliseum.

But this will be Melvin's first time back as manager at Chase Field, and that will provide a new element.

"It is the first time back, and it's a great team that doesn't have the type of record that they're probably going to finish up with," Melvin said. "I spent some time there and have a lot of good friends there still. There's certainly something added to it."

Scribner ready for opportunity with A's

OAKLAND -- New A's callup Evan Scribner didn't exactly set the world on fire in his one previous stint in the big leagues, recording a 7.07 ERA over 14 innings with the Padres last season. But after a successful stint with Triple-A Sacramento, and with his health restored, the pitcher feels like he's more prepared for the Majors this time around.

Scribner, brought up by Oakland on Wednesday after reliever Andrew Carignan was lost for the year with a right elbow sprain, said on Thursday that he wasn't expecting a promotion anytime soon, but Carignan's injury changed that.

The right-hander blamed his struggles in San Diego last season on a sore pitching arm that had been bothering him all year. To make matters worse, Scribner then partially tore a lat muscle in his back in July. But he's come all the way back from his health issues, posting a 3.31 ERA and striking out 35 batters in 32 2/3 innings for Sacramento.

A's manager Bob Melvin said Scribner's ability to go long was the main factor in his callup.

"Right now, with some of our younger starters, we're kind of limiting them a little bit, not getting them too much over 100 pitches," Melvin said. "I think it's nice we have some length. He's closed games down there, he's pitched a couple innings. We saw in Spring Training, he pitched well for us, and I think he can give us a versatile guy.

"Based on what we heard from our Triple-A coaches and managers, he was the one who was ready and suited to help us out right now."

Other bullpen callups this season, including Carignan and right-hander Graham Godfrey, haven't been able to make a lasting mark in the big leagues. But given that Carignan is now out for the season, Scribner has an opportunity to convince the A's brass that he should be up here for good.

"If you do well, and you give them a reason to keep you around, then you don't give them a reason to send you back," Scribner said. "It's always going to be a good opportunity. You just have to take advantage of it."

Worth noting

• A's manager Bob Melvin said that utility man Josh Donaldson will probably start Sunday's game in Arizona at catcher to give regular backstop Kurt Suzuki a break. Donaldson, hitting .148 for the season, filled in at third when Brandon Inge was on the disabled list, but hasn't received much playing time since Inge returned.

• Oakland's starting pitchers have been taking batting practice in recent days to prepare to hit during the upcoming games in National League parks. Melvin reported that right-hander Jarrod Parker and left-hander Tommy Milone, in particular, have looked good while swinging the bat.