In 2009, the Twins scored 817 runs, ranking them fourth in the American League. They hit 172 home runs, which -- while below the league average -- marked their highest total in the past six years and an increase of 61 from the prior season.

They managed this relatively gaudy offensive production despite underwhelming performances from such regulars as Alexi Casilla, Nick Punto, Joe Crede, Delmon Young and Carlos Gomez.

The lineup's overall success in '09 was keyed by four players that comprised the heart of the lineup: Joe Mauer, Justin Morneau, Michael Cuddyer and Jason Kubel. Each of the four posted an OPS of .862 or higher, went deep at least 28 times and drove in at least 94 runs, transforming an otherwise sub par offense into one of the best in the league.

Last year, the Twins' lineup featured greater balance, but scored 45 fewer runs and hit 30 fewer homers. To pinpoint this drop-off in production we need look no further than those four players.

Mauer struggled with injuries and adjustments to his new home park; his home run total dropped from 28 to nine and his OPS dropped by 160 points. Morneau was tremendous over the first half of the season but didn't play a game after July 7, finishing with career lows in home runs (18) and RBI (56). Cuddyer never seemed to get his power swing going, tallying less than half as many home runs as the previous year (from 32 to 14) and posting the lowest full-season slugging percentage of his career (.417). Kubel saw his OPS drop from .907 to .750.

In my opinion, the lineup has gotten worse around these four players since last year. I see Alexi Casilla and Tsuyoshi Nishioka as offensive downgrades from Orlando Hudson and J.J. Hardy, and I have a hard time expecting the same kind of production from the likes of Jim Thome and Danny Valencia.

Even if those auxiliary players don't pan out as the team hopes, though, it doesn't mean the offense can't be more productive overall. If the four players at the heart of the order can move closer to their 2009 levels of production, they can change the entire complexion of the lineup, especially with Delmon Young now adding another legitimate power bat to the mix.

Whether or not these hitters can rebound will be largely dependent on health. It seems fair to say none of the four were completely healthy last year, and unfortunately three of them are already dealing with injury issues this spring that have prevented them from being able to take the field for a game thus far.

If the "Core Four" can put these pesky problems behind them and remain relatively healthy throughout the summer, they could easily be the difference between a mediocre lineup and an upper-echelon one.