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4/22/2014 7:57 P.M. ET

Porter's advice working wonders for Fields

SEATTLE -- After Astros relief pitcher Josh Fields gave up three hits and two earned runs in his fourth outing of the season on April 10 in Toronto, manager Bo Porter pulled him aside and told him he didn't appear to be ready to come into the game.

Then Porter gave Fields a tip: to approach warming up in the bullpen during the game and again during his eight warm-up pitches on the mound like he's facing hitters.

"'So you have a lather and have some blood flow going to where you feel like when the guy steps in the batter's box, you're actually facing a third guy,'" Porter told Fields. "He took heed of that advice and since that Toronto outing, I feel like he's thrown the ball really well."

Indeed. Fields has thrown 4 1/3 scoreless, hitless innings in four outings since his chat with Porter in Toronto. He struck out all three batters he faced in the ninth inning in Monday's series opener against the Mariners, lowering his ERA to 2.25.

"Guys are different out of the bullpen," Porter said. "It looks to me the times in which he struggled, even dating back to last year -- I went through some of the notes in which I wrote down -- it seemed he came into the game and wasn't ready to pitch. All of a sudden, before you know it, you walk two guys and start popping 96 [mph]. You say, 'Why didn't you throw your 95, 96 mph fastball from the beginning?' You address it by bringing it to the player's attention and hopeful they're able to do something about it."

Fields has found himself a home in the Astros' close-knit bullpen and said veterans like Matt Albers, Chad Qualls and Jerome Williams are doing wonders for him.

"These guys have really been looking out for us and taking us under their wing and taking care of us," Fields said. "It's been a blast and a privilege to be a part of it. I'm looking forward to hopefully playing a long time with these guys. We'll see about that, but it's a lot of fun."

Harrell outrighted to Triple-A after clearing waivers

SEATTLE -- Right-hander Lucas Harrell, who began the year in the Astros' rotation, cleared waivers on Tuesday and was outrighted to Triple-A Oklahoma City, but it's not known whether he will actually report to the RedHawks.

Because he has no prior outrights and has less than three years of Major League service time, Harrell can't elect free agency. He has 72 hours to report to Oklahoma City.

Harrell went 0-3 with a 9.49 ERA in three starts with the Astros before being designated for assignment last week.

Harrell hasn't been able to duplicate his 2012 breakout campaign in which he was 11-11 with a 3.76 ERA in 32 starts. He struggled to find consistency last year and wound up leading the American League in walks and losses while teetering between the rotation and bullpen.

Harrell told MLB.com last week it's probably time to move on.

"They've got their plans and I understand that," he said. "I think it's best for both parties to kind of go their separate ways."

Harrell's spot in the rotation was taken by Brad Peacock, who allowed five hits and two runs in a loss at Oakland on Sunday.

Prospect Amador loaned back to Mexican club

SEATTLE -- The Astros have decided to loan burly slugger Japhet Amador to Los Diablos Rojos de Mexico for the remainder of the Mexican League season, which runs through August. He hit .214 with eight RBIs in seven games for Triple-A Oklahoma City, but hadn't played in 10 days due to an injury.

Oscar Suarez, the agent for Amador, said the Astros can decide at the end of the Mexican season if they want bring Amador back to play at Triple-A. He said the Astros had until May 3 to buy him or not, but with Jon Singleton ahead of him in the depth chart at first base, it made sense to send him back.

"He would have rather stayed here and kept playing here, but the Mexico City Reds want to win down there, too, which makes sense when you look at it," Suarez said. "They'll decide [at the end of the season] if they want to bring him back, which they probably will, and take a look at him and hopefully he'll be in shape and ready to go."

Amador, signed last year out of the Mexican League, was late reporting to spring camp because of complications with his wife's pregnancy in Mexico. He began the season with the RedHawks, getting most of his at-bats at designated hitter.

Amador hit 36 home runs for Diablos Rojos del Mexico last year, leading the team in homers and RBIs, with 121. In 104 games and 449 plate appearances, Amador struck out only 59 times.

Brian McTaggart is reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.