With the moves, 46 players remained in Major League camp, including 23 pitchers.
"We're at the fourth time through, starting today, with the starters, so the innings are going to get tighter," Brewers manager Craig Counsell said, a hint that Junior Guerra will get the start on Opening Day. "A group of those guys are Triple-A starters, so they need to continue building up pitches. It's just running out of innings."
Hader, Milwaukee's No. 3 prospect and the top left-handed-pitching prospect in baseball according to MLBPipeline.com, is expected to open the season in the Triple-A Colorado Springs rotation with Espino and Wilkerson. Lopez, Milwaukee's No. 13 prospect, is another candidate for that group, but his assignment has yet to be finalized, Counsell said. Barring a setback in his comeback from Tommy John surgery, Williams could start at Double-A Biloxi.
Monday's news still stung, Hader said, even though the chances of him making the Opening Day roster were slim. He approached this spring as if he was bidding for the Brewers' Opening Day roster
"That's anybody's mindset, even if I have a chance or not," he said. "You want to be in the big leagues."
Said Counsell: "I think he has a good chance to impact this team this year. When we have a need, make it an easy decision for us."
Lopez and Team Puerto Rico are moving on in the World Baseball Classic, but Hader and Williams will get right to work in Minor League camp on Tuesday, when both are scheduled to pitch in an intrasquad game. For Williams, who missed each of the past two seasons with an injured elbow, it will mark his first game action of the spring.
"I was a realist coming into camp. … Coming off injury, I understood I was here to get my work in, get better and absorb everything," said Williams, who has a chance to open the season at Double-A Biloxi. "I was here [three] years ago, but I felt more comfortable and mature this time. I just have a better understanding of how to take care of myself and how to go about my business on a daily basis."
Minor League Spring Training games begin on Friday.
Adam McCalvy has covered the Brewers for MLB.com since 2001. Follow him on Twitter @AdamMcCalvy, like him on Facebook and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.