By Larry Fine

NEW YORK (Reuters) - The All-Star Game has come and gone and it is back to business in Major League Baseball, both on and off the diamond as teams ponder whether it is time to buy or sell talent with the Aug. 1 trade deadline looming.

All 30 clubs return to action on Friday following the All-Star break for a second-half push that will settle berths in the postseason playoffs leading to the World Series.

Impactful players including Brewers catcher Jonathan Lucroy, slugger Jay Bruce of the Reds, Oakland starting pitcher Rich Hill and Yankees closer Aroldis Chapman are among presumed trade targets of contenders.

Last year, eventual World Series champions Kansas City Royals added starting pitcher Johnny Cueto and versatile regular Ben Zobrist, and National League pennant winning New York Mets turned their season around by adding slugger Yoenis Cespedes.

It takes two to tango, of course, so struggling teams such as the Oakland A's, Tampa Bay Rays and Cincinnati Reds are taking hard looks at their rosters with their future in mind.

Eighteen clubs are within five games of a playoff spot with three division titles and two wildcard berths at stake in both the American and National League.

With demand strong, promising prospects could be changing hands in order to get an instant boost, giving teams on the bubble a delicate dilemma.

One such club is the New York Yankees, who after adding Cuban fireballer Chapman to in-house relievers Andrew Miller and Dellin Betances in a pre-season trade with Cincinnati, have a troika of top-rate closer candidates.

The Yankees (44-44) cherish their winning tradition and 27 World Series crowns but stand 5 1/2 games out of a wildcard berth with six teams to leap over and have been keen to get younger on the field.

Among their aged veterans is 39-year-old outfielder Carlos Beltran, who is enjoying a standout season with 19 home runs and becomes a free agent next year.

Among teams that figure to be in the market for starting pitching are the AL-West leading Texas Rangers, AL-East leading Baltimore Orioles and their division rivals the Boston Red Sox.

NL West-leading Giants and NL Central frontrunners the Chicago Cubs could use an end-of-game reliever.

Available starters could come from the Rays (34-54), who may be tempted to swap Matt Moore, Drew Smyly or Jake Odorizzi for promising players, while Jeremy Hellickson of the Phillies and Drew Pomeranz of San Diego be moved for the right price.

Oakland outfielder Josh Reddick and third baseman Danny Valencia, along with Angels' third baseman Yunel Escobar and perhaps three-time All-Star Carlos Gonzalez of the Rockies are other trade options for offensively-needy contenders.

The Mets, Giants and Dodgers in the National League and the American League Central-leading Indians and division rival Kansas City could be looking to beef-up their attacks.

The blueprint for a playoff run is imprinted on the braintrusts of title dreamers, emboldened by the 2015 Royals and Mets, and Toronto's charge to the AL Championship Series after adding slugging shortstop Troy Tulowitzki and starter David Price.

Who wants to build this season's powerhouse?

(Editing by Frank Pingue)