A baseball pitcher's job boils down to a simple quest: Keep the batter guessing. What's coming next? Curveball? Changeup? High heat?

So it's only fitting that Stillwater author Rick Shefchik's second sports mystery, "Green Monster," succeeds by keeping the reader as off-balance as a slugger out front on an off-speed pitch.

Shefchik's first book, "Amen Corner," introduced us to Sam Skarda, a blues-playing Minneapolis cop turned private investigator who defuses a criminal plot threatening to stomp on the azaleas at golf's most sacred acreage, Masters venue Augusta National.

In Skarda's second go-around, we get down and dirty in Boston's answer to Augusta National -- quirky Fenway Park, home of the Red Sox and the fortress wall in left field from which the book draws its title.

The book opens by introducing the happy owner of the Red Sox, Lucky Louie Kenwood, who served as the king of Red Sox Nation as the team finally shook off decades of sour luck by winning two World Series.

Things couldn't be better. Sure, Kenwood's second wife is a chain smoker nearing death, but his fetching blonde assistant, Heather Canby, extends her business expertise beyond the front office.

It's Canby who calls Skarda after Kenwood receives a $50 million extortion note, threatening to go public with a story that the 2004 World Series was thrown. The note is signed Babe Ruth, as in the Curse of the Bambino, the hex that covered the Bosox since trading Ruth to the Yankees.

That's where the guessing game kicks in, with Shefchik throwing an array of pitches to readers, who don't need to love baseball to get hooked by the narrative.

There's Paul O'Brien, Kenwood's loyal driver with some checkers in his South Boston background.

There are a couple baseball stars in the steroids/human growth hormone era, who happened to be Cardinals on the losing end of the 2004 Series. But what's $50 million to these guys?

There's Kenwood's cross-dressing son, who everyone thought had drowned, not to mention a collection of Los Angeles mobsters.

And then there's Canby, the driven, sex-crazed front-office assistant with a heart that pings like an aluminum bat.

Duluth-born and a longtime St. Paul Pioneer Press reporter, Shefchik's 1990s parenting column was a staple for Twin Cities readers. Now that his two kids have grown up and the newspaper business is littered with refugees, it's nice to see him reinventing himself as a big-league spinner of mysteries.

Curt Brown is a general assignment reporter at the Star Tribune. His first book, "So Terrible a Storm," will be published in November by Voyageur Press.