When Missouri softball coach Ehren Earleywine first told his shortstop, Jenna Marston, after last season that he wanted to move her to catcher, she thought he was joking.

"I laughed," she recalled this week. "Then I realized he was being serious."

Making the move from shortstop to catcher is not just rare, it's a practically unheard of. Adding more to the move, Marston, a two-time all-Big 12 selection at shortstop, would be replacing Megan Christopher, who the year before had been the conference co-defensive player of the year.

Once the shock wore off, Marston said OK and went about learning a position she had only a fleeting exposure to and had little or no connection to what she had been doing the previous two years.

She has handled the switch well, and reviews on her catching are favorable.

"She's amazing back there," said Mizzou ace Chelsea Thomas. "She's made so many strides over the year, I'm happy to see her back there. She's working hard and doing really well. ... She's a trouper, that's for sure."

"I really didn't know how it would go," Marston said. "It was a big experiment. We've got really good pitchers and replacing Megan Christopher is tough job. I think it's gone really well."

The ninth-seeded Tigers face Louisiana State in an NCAA super regional at University Field on the Mizzou campus in Columbia. Game 1 of the best-of-three series will be Saturday at 6:30 p.m. Game 2 will be Sunday at 2:30 p.m., and if a Game 3 is needed, it will be played Sunday immediately after Game 2. The winner moves on to the Women's College World Series.

Marston had caught in her senior season at Principia high in St. Louis. When Earleywine looked at his team and thought about a replacement for Christopher, Marston was, to him, the obvious candidate.

"You just think we'll get her 25, 30 games into the season and if it doesn't work, we'll run her back out to shortstop or center field," he said. "But anybody on our team that watches our practices will tell you that J.J. is far and away the best catcher on our team."

That doesn't necessarily mean it's easy. Earleywine knew Marston would have to overcome her inherent cautiousness in changing positions.

"J.J. is such a careful person, such a calculated person," he said, "that in order for her to try something new behind the plate, it takes a lot of courage for her to do that. It's just not in her nature. She's very conservative. She's steady, she catches the ball, she throws it back to Chelsea, she doesn't let the ball get past her, she's hitting .300, and that's kind of who she is. For her to do a lot more than that, I don't know."

"He's right," Marston said. "I like to feel comfortable when I play and making drastic changes isn't easy for me. At the beginning, I felt really uncomfortable because I'd never done it before. It was so different, but it didn't really bother me. I didn't feel as comfortable as now, but I never felt like something was really wrong."

Earleywine believes it took Marston about 15 games to get comfortable behind the plate. Her batting average has come down from .311 last season to .301 this season — she's not sure if the switch is the reason — but she set the school record for walks in a season with 45. On Thursday, she was named an Academic All-American, Mizzou's first in softball in more than 20 years. She has a 3.98 GPA and is majoring in industrial engineering.

Marston can certainly feel the difference between catching and playing short in her legs after games and she's found the throws, particularly to second, to be different from what she had to do as a shortstop.

"It's just a different mentality back there," she said. "You're in every play. There's not really any down time back there. It's kind of nice. It puts you in a game the whole time."

When Marston caught at Principia, she never thought she was a catcher, just someone filling in. At first, she had the same feeling at Mizzou.

"When people ask what position I play, I say catcher," she said. "For a long time, through the start of season, I said wherever, catcher, shortstop, outfield. Now I just say catcher. I do feel comfortable back there. I've still got some stuff I can work on, keep improving.

"It's been a fun experience. I've enjoyed catching. If that's what coach wants, then whatever keeps me in the lineup."