HILLSDALE -- A large blue tarp covers the infield at Hillsdale College’s Johnny Williams Field. Tractor tires dot the large plastic covering as puddles begin to form from the steady rain.

No softball will be played here today. The shallow 190-foot fence in left field is safe from the powerful swing of Grand Valley State’s Katie Martin.

Like the game at Hillsdale earlier this week, Martin’s offensive onslaught was only postponed. On Thursday, she went 4-for-8 with her 14th home run of the season in a doubleheader sweep of Northwood.

The 2009 Pioneer High School graduate leads the Great Lakes Intercollegiate Athletic Conference in batting average (.513), RBIs (40), doubles (10), home runs (14), total bases (98), on-base percentage (.602), and slugging percentage (1.150).

She is second in hits (44), runs (34) and walks (16). Nationally, Martin leads all of Division II in home runs per game (.52) and is fourth or better in five other offensive categories.

Oh, and by the way, she’s 7-1 on the mound as a pitcher for Grand Valley (23-4, 9-1).

It’s enough to give opposing coaches nightmares.

“The way she’s hitting you’ve got to try and keep the ball down (in the strike zone),” says Hillsdale coach Jamie Meyers. “She had a ridiculous amount of home runs last year too, so for the power numbers it’s not really that different.”

Martin was Freshman of the Year in the GLIAC last season, one year after setting Pioneer school records for batting average (.631) and home runs (11) in a season.

Former Pioneer softball coach Elissa Brode theorizes that the consistent speed she sees from college pitchers helps Martin’s power numbers. The extra speed doesn’t faze her, but it does generate extra velocity when the ball leaves the bat.

“I’m not surprised at all by her transition to the college game. When I first saw her play as a freshman (in high school), she was the best hitter I’d ever seen,” Brode said. “She started hitting home runs and people stopped pitching to her.

“Her senior year, people barely pitched to her. She hit 11 home runs and that was all in just a few double headers at the beginning of the season. After that she hardly ever got a pitch to hit.”

Martin credits her discipline at the plate for the spike in numbers. Grand Valley coach Doug Woods agrees.

“Last year, she might go after a pitch out of the strike zone. This year she very rarely does that,” Woods said. “If she swings at a pitch, it’s a pitch around the plate and I think that has helped her out tremendously.”

The sophomore has 23 home runs for her career, putting her just two away from second-place in school history. The career record at Grand Valley (and in the GLIAC) is 46.

But it’s batting average - not her power - that Martin takes the most pride in.

“(Batting average) just shows that you’re hitting the ball, be it singles or whatever,” Martin says. “(Hitting a home run) it is an awesome feeling, but you can’t go up to bat thinking about that. Just go up looking for a single every single time and just - with good form - it’ll go.”

Martin continues to get good pitches to hit because the 23-4 Lakers have power all over their lineup. Combined, Martin and Howell High School graduate Miranda Cleary have more home runs than every other team in the GLIAC.

“Having other people in the lineup really helps because if you have just one hitter doing well, they’ll walk (Martin),” Woods says. “I’m just hoping that doesn’t happen. But if it does, Katie will handle that.

“She knows getting on base, whether it’s a walk single, whatever is very important to the team.”

Martin chose Grand Valley over preferred walk-on offers at Division I schools, including Michigan - not to mention offers to play field hockey at Duke and Michigan State.

She likes the coaching staff at Grand Valley, the school has her major - biomedical engineering - and it wasn’t too far from home.

Plus, at the DI schools, she wasn’t as likely to be allowed the opportunity to pitch and hit.

“We liked her because she’s a two-pronged person. She’s a heck of a hitter and a very good pitcher, too,” Woods says. “She’s an intense player and does not lose focus.”

Pete Cunningham covers sports for AnnArbor.com. He can be reached at petercunningham@annarbor.com or by phone at 734-623-2561. Follow him on Twitter @petcunningham.