FORT MYERS, Fla. (AP) -- A shaky afternoon on the mound quickly became a most memorable day for Shelby Miller.
The 22-year-old rookie pitched into the fifth inning, then found out he'd won the fifth spot in the St. Louis rotation as the Cardinals beat the Minnesota Twins 4-3 Monday.
Miller gave up one run and six hits in 4 1-3 innings. He struck out two and walked two.
After the game, manager Mike Matheny said Miller would be a starter. Joe Kelly, who also had been competing for the No. 5 slot, will make the roster as a long reliever.
''I'm grateful for the opportunity,'' said Miller, a first-round draft pick in 2009. ''I'm humbled. It's an unbelievable feeling.''
''I'm still kind of taking it all in. To be the fifth starter for any team is amazing. To be playing for the St. Louis Cardinals is different. It's one of the best-respected organizations in baseball. I'm looking forward to the opportunity I have. I'm playing behind some of the best players in the league,'' he said.
Miller has a spring ERA of 3.94. Kelly gave up two runs and two hits in two innings, bringing his spring ERA to 5.54.
''I was definitely struggling early,'' Miller said. ''I definitely didn't have my best stuff at all. I still battled.''
Miller made his big league debut last year and went 1-0 with a 1.32 ERA in six games. The 6-foot-3, 215-pound righty said he took a different approach this past offseason.
''I made a goal to put on a lot of muscle and weight and come in with a different body,'' Miller said. ''I feel like I did that. I'm trying to do the little things right to try and make me a better pitcher.''
Matheny said even after Miller's worst outing of spring training that he deserved the fifth spot.
''We explained to him in a year's time the maturing in his game and as a person - it's just off the charts,'' Matheny said. ''He's trending in a great direction. He just has to keep that going. There's a bright future for him. Remember what got him to this point.''
Miller earned his first big league win during a call-up from the minors late last season. He was 11-10 with a 4.74 ERA in 27 starts at Triple-A Memphis, striking out 160 in 136 2-3 innings.''
''It was an important time of the season to bring him up last year, and we got to see him grow and improve and give us a glimpse of what he could be,'' Matheny said. ''And Joe Kelly, too. Let's not forget he'd never made an opening day roster. It's a huge accomplishment for him to make our bullpen. He gives us some depth and a long guy if we need him.''
Twins starter Mike Pelfrey struck out four, walked one and gave up one run and five hits in five innings. He has a 5.52 ERA after five spring starts.
''It's definitely better than the last time I pitched here,'' said Pelfrey, who is coming off Tommy John elbow surgery last May. ''I'm making progress. I'm pleased with where we're at. The biggest thing is, I walked out there and I felt good.''
NOTES: Joe Mauer had two hits and a walk for the Twins, raising his spring batting average to .435. ... The Twins optioned C Drew Butera to Triple-A Rochester and reassigned C Dan Rohlfing, OF Brandon Boggs and INFs Jeff Clement and Ray Olmedo to minor league camp. ... Twins manager Ron Gardenhire said barring a late change or injury, OF Wilkin Ramirez will make the 25-man roster as a bench player. Ramirez is hitting .415 (17 for 41) this spring with a team-best seven doubles. ''He's fantastic in the clubhouse with the younger kids,'' Gardenhire said. ''We really enjoyed him and he just did better than the other guys.''