Pittsburgh is about to see what Jack Wilson truly means to the Pirates.

The 30-year-old… Pittsburgh is about to see what Jack Wilson truly means to the Pirates.

The 30-year-old shortstop landed on the disabled list for the first time in his eight-year career last Sunday after sustaining a strained calf three days earlier against the Atlanta Braves.

The determined Wilson fought to stay off the disabled list, claiming he wouldn’t need the 15 days to get all healed up. But with second baseman Freddy Sanchez periodically missing games with a shoulder injury as well, Pittsburgh’s hands were tied with its middle infielders.

So off to the training room Wilson went. The Pirates’ chances for a successful April might have followed him.

I know Adam LaRoche’s early and typical April woes and Jason Bay’s continual slump are likely facilitators of a quick demise, but Wilson’s absence can’t be overlooked.

Only last July, it appeared that the longest-tenured Bucco would be packing his bags for Detroit. At the trading deadline, then-general manager Dave Littlefield had a package set up to ship Wilson to the Tigers for pitching prospect Jair Jurrjens and another top minor leaguer.

For some unknown reason, Littlefield scrapped the trade and instead acquired an aging light-tossing softball pitcher who had apparently stolen Matt Morris’ body. And his roughly $10 million salary. Ouch.

Additionally, Wilson didn’t seem to be happy with the previous management and also had occasional spats with former manager Jim Tracy. Tracy pushed for the acquisition of Cesar Izturis, a favorite of his in Los Angeles.

So all “Jack Flash” did was hit the snot out of the ball in August and September, with monthly averages of 0.362 and an astounding 0.460 respectively.

With the firings of Littlefield and Tracy and the entrances of general manager Neal Huntingdon and manager John Russell, Wilson was happy again with the possible direction of the team.

The shortstop didn’t have the greatest start to 2008, committing a costly error in the Atlanta series and going only 1 for 12 at the plate. But that one was a difference maker: a tying single on Thursday that helped the Pirates eventually win the game.

But as Wilson ran toward first, his calf worsened after sliding into the previous inning, and the injury initially looked serious. He couldn’t even walk off the field.

So the time has finally come for the Pirates to observe their shortstop situation without Wilson, and it isn’t pretty.

Spring standout Luis Rivas manned the position over the weekend against the Florida Marlins and in the home opener against the Chicago Cubs. Rivas used to play second base for Minnesota, and while his defense was lauded in spring training it hasn’t been up to par thus far.

Rivas has been serviceable with the bat, but the fielding has been atrocious at times. He already has three errors and at least two of them were on simple ground balls.

His error in the 10th inning on Monday almost gave the Cubs the runs they needed to win.

Rivas is a bench player, plain and simple.

The only Pirates alternative at shortstop is rookie Brian Bixler, who was called up to replace Wilson on the active roster.

Pirate fans promptly booed Bixler in the bottom of the ninth on Monday when he pinch-ran for Ryan Doumit and didn’t score from third when Jose Bautista tried to bunt him home.

It was kind of harsh treatment for the young shortstop who was only playing in his second major league game, but he has to be ready to produce in a hurry.

Rivas’ lousy defense has pretty much guaranteed that Bixler will start practically every game from here on out until Wilson is healthy.

Bixler looked like a legitimate prospect in the first half of last season in the minor leagues. But his numbers dropped quickly in the latter portion of the year, and he looked lost in the spring as well.

At best, Bixler looks like a utility infielder at this point. Oh, I forgot to mention: From all reports, Bixler’s defense would make Rivas look like Ozzie Smith.

The Pirates’ left side of the infield might start mimicking a T-ball game soon.

The only other prospect at shortstop in Pittsburgh’s system is Brian Friday, but he’s way down in Class A. He won’t be ready for a few years at the earliest.

While Wilson is a fan favorite in Pittsburgh, many analysts and dedicated supporters have called for a trade of the shortstop. At this stage in the Buccos’ development, that would be flat-out ridiculous.

Bixler doesn’t seem to be an everyday player, and there is absolutely no one in the system who could replace Wilson and be as productive. Wilson is a Gold Glove-caliber shortstop, while his smarts have been increasing at the plate as he ages.

Pittsburgh can’t afford to have more balls skidding between its shortstops’ legs. The errors will start costing the team games if they aren’t reduced immediately. The offense has directed some impressive comebacks thus far, but it may not hold up much longer, especially if Bay and LaRoche don’t turn it up a notch.

If the Pirates have only 10 wins at the end of April, Wilson’s absence will be the cause. And the team likely won’t sniff 0.500 again.