Despite a state Supreme Court decision this week that appeared to throw them a curve ball, Major League Baseball officials were back on the streets of Philadelphia today on the lookout for vendors hawking counterfeit Phillies merchandise.

On Monday, Pennsylvania's high court overturned the state's trademark counterfeiting law, ruling that it was worded so broadly that it violated First Amendment rights to free speech.

But intellectual-property lawyers and MLB officials said that even if the state's anti-counterfeiting law proved temporarily unenforceable, other civil and criminal laws would enable them to continue efforts against blatant counterfeiting - a problem that tends to mushroom when teams make it into postseason play.

As the Phillies prepared for their first playoff game today, four undercover teams were at work in Philadelphia, according to Ethan Orlinsky, general counsel for Major League Baseball Properties.

Orlinsky said each team consisted of two to four investigators, typically off-duty or retired police officers or detectives. Their goal is to find and seize counterfeit merchandise under the terms of a federal civil-seizure order, which the league renews each year.

"They'll be combing the entire Philadelphia area, not just the ballpark, wherever counterfeits might be sold," Orlinsky said today. "We focus on areas where fans or other consumers might make an impulse purchase."

In Philadelphia, that might mean on the streets of Center City or near subway stops, as well as around parking areas near Citizens Bank Park. Teams were already on the street during Tuesday's Phillies rally at Liberty Place.

Last year, similar teams of investigators seized thousands of counterfeit T-shirts and hats from dozens of vendors. To help fans tell what's legitimate, MLB requires that each licensed item be tagged with a silver holographic sticker bearing a serial number and MLB's silhouetted-batter logo.

Ironically, the Phillies world championship last year may tamp down counterfeiters' success this year, unless and until the team starts winning some playoff games. Orlinsky said that during Atlanta's long string of postseason play, "there were fewer sales of counterfeit merchandise as the team continued to win year in and year out."

Trademark lawyers said Monday's ruling by the state Supreme Court was likely to have little impact on efforts such as those by Major League Baseball, even if it throws a wrench into efforts at local enforcement of the state's criminal anti-counterfeiting law.

"If the legislature wants to fix this, they could fix it in 15 minutes," said Stuart Rudoler, a Bala Cynwyd lawyer who specializes in civil trademark law.

"The Pennsylvania Supreme Court wasn't saying you can't criminalize counterfeiting," Rudoler said. "They were saying you can't make it so broad that you would criminalize wearing a T-shirt that says, 'I love the Phillies.' "

In Monday's 4-3 ruling, the state Supreme Court held that a Centre County court had properly dismissed charges against two men accused of violating the state statute.

One had been stopped for speeding when officers found boxes of what appeared to be counterfeit Nike sneakers in his car. The other was accused of hawking hats bearing the Penn State logo outside Beaver Stadium on the Penn State campus.

Agreeing with the Centre County judge, Supreme Court Justice Max Baer wrote that the law was so broad that it would bar "the use of words on a sign praising or protesting any entity with a trademarked name, including Penn State. Taken to the extreme, even our use of the words 'Nike' and 'Penn State' in this opinion without the permission of the company or university would fall under the current definition of a counterfeit mark."

Polk Wagner, a professor at the University of Pennsylvania law school who specializes in intellectual-property issues, said the ruling could interfere with criminal prosecutions. But he said the unusual degree of overlap between state and federal trademark laws meant that at least some anti-counterfeiting efforts could still proceed.

Wagner called the state law "a very poorly drafted statute," and added, "One suspects that the legislature will move very swiftly to fix it."

Contact staff writer Jeff Gelles at 215-854-2776 or jgelles@phillynews.com.