WEST PALM BEACH, Fla. -- Left-hander Reymin Guduan appears to be the favorite to land the final spot in the Astros' bullpen, while manager AJ Hinch acknowledged on Tuesday that veteran right-hander Brad Peacock is his leading candidate to join the starting rotation.

Guduan has 12 strikeouts with two walks, and he has allowed just two earned runs in eight innings over eight outings. He was vying for the final spot in the bullpen with lefty Cionel Perez, who was optioned to Minor League camp on Tuesday, and Peacock. Lefty Framber Valdez was battling with Peacock for the final rotation slot and could still be a factor in the bullpen.

"Pitching-wise, we still have a little bit of time to make a decision," Hinch said. "In a perfect world, we would have already made a decision. You start to transition someone to the bullpen, either Peacock or Valdez, going to the 'pen or send them out or give them regular work. We're just not ready to make a decision yet."

After appearing in eight games in his Major League debut last year, Perez started his throwing program late in the offseason and he was behind when camp started. He's appeared in only two games this spring, and Hinch said the club felt it was more important for his development to get regular work at Triple-A Round Rock to start the year.

"We think he's going to pitch in the big leagues this year, most likely out of the bullpen," Hinch said. "Given our needs in the 'pen and how it's shaping up, we had guys ahead of him and so we decided to make the decision today."

Rain shuffles pitching order

Tuesday's rainout forced the Astros to alter their pitching plans. Gerrit Cole, who was supposed to start against the Phillies on Tuesday, will throw two to three innings in a simulated game Wednesday. Lefty Wade Miley will get the start Wednesday at the Ballpark of the Palm Beaches against the Yankees at 1:05 p.m. ET.

"Rotation-wise, it doesn't really change a ton, other than it changes the workload Cole is going to have," Hinch said. "One of these next two starts was going to be a low-volume start for him anyway, and we'll just have to have it be this one because of the rain."

Meanwhile, right-handed starter Collin McHugh will throw in a Minor League game on the back fields on Wednesday, along with a handful of relief pitchers.

"Blows up every plan we had this week, which is an important week going into the season," Hinch said of Tuesday's washout. "It's not insurmountable."

Cole is scheduled to start the Astros' second game of the season, March 29 against the Rays in St. Petersburg. Justin Verlander will start on Opening Day on March 28. Hinch hasn't yet announced how the rest of the rotation will line up after that.

Revolving door at DH

The departure of Evan Gattis in free agency -- he's still unsigned, by the way -- and the Astros' decision not to carry a true designated hitter will lead to a revolving door at that position this year. Hinch said the at-bats at DH will be about trying to find ways to be creative with the versatility of the rest of the roster.

Tyler White is expected to get most of the at-bats at DH, but outfielder George Springer could see plenty of at-bats at DH as well, as Hinch looks for ways to get outfielders Tony Kemp and Jake Marisnick in the lineup.

"If Whitey is hitting the way he hit in the second half last season, he might factor in more than I'm giving consideration," Hinch said. "I think we need to utilize the whole roster. That's more the motivation than any sort of scientific study on rest. I just want to play our guys and that's one spot that continues to need to be rotated."