Miller, the overall No. 5 prospect, made two Grapefruit League appearances before getting reassigned, allowing four earned runs over 4 1/3 innings. The Cardinals want the 21-year-old to continue pitching on regular rest as he prepares for the Minor League season, which begins April 6. After going 11-6 across two levels last year, Miller could open the season at Double-A Springfield or Triple-A Memphis.
The Royals sent down three of their top four prospects, including left-hander Mike Montgomery, who nearly earned a spot in the Major League rotation last spring. The left-hander, MLB.com's No. 21 prospect, was a disappointing 5-11 with a 5.32 ERA at Triple-A Omaha.
Joining him at Minor League camp were outfielder Wil Myers (No. 19) and right-hander Jake Odorizzi (No. 47). Myers, a member of the Arizona Fall League Top Prospects Team, batted .315 in nine Cactus League games.
Shortstop Hak-Ju Lee, the Rays' top prospect among position players, was one of the team's first roster cuts. In his first season after coming over from the Cubs organization in the Matt Garza trade, Lee hit .292 with 33 stolen bases and 98 runs scored between Class A Advanced Charlotte and Double-A Montgomery.
Outfielder Brett Jackson remains in Major League camp, but Cubs manager Dale Sveum said Wednesday that the team's No. 2 prospect almost certainly will open the season at Triple-A Iowa.
"We have to remember that developing is just as important as anything else," Sveum told MLB.com. "Unfortunately for him, there's no job openings. It's one of those things -- timing and a numbers thing. He'll spend a long time here, and part of that development plan is what it is. He hasn't spent a whole year in Triple-A, and we have to see what's happening after the halfway mark and make your decisions there."