If the Earthquakes plan to reach the Major League Soccer playoffs, they will have to do it without recent acquisition Edmundo Zura.

The team sent the Ecuadorean striker home this week after he failed a physical and was deemed unfit to play, the team announced Wednesday. The Quakes terminated a loan deal with El Nacional of Ecuador that brought Zura to the United States in what amounted to an audition to earn a contract for 2012.

The development has led some fans to question the Quakes’ leadership, but president David Kaval said the jobs of general manager John Doyle and coach Frank Yallop are secure.

“Frank and John are an integral part of our success now and in the future,” he said of the men who have been signed to long-term contract extensions. “I’m very confident in our ability to put a high-quality team on the pitch.”

The Earthquakes are 15th out of 18 MLS teams in points with eight games left. Although not mathematically eliminated, they are likely to miss the postseason for the third time in four years since re-entering the league as an expansion team in 2008.

Kaval said the Zura deal underscored the need to build a better system to evaluate international talent. He promised to invest more resources in scouting and analysis of foreign players because “in this day and age, the league is getting more competitive and you have to do that.

“We’re not in the business of signing a $10 million no-brainer guy. The (Los Angeles) Galaxy and (New York) Red Bulls are the only teams in the league who can do that.”

However, Kaval acknowledged that relying on others’ opinion doesn’t work as illustrated with Zura, a 27-year-old Ecuadorean national team player.

“The only way to be effective with that is to have your own horse in the game,” he said.

The Zura loan deal didn’t cost San Jose anything other than the embarrassment of trying to find 11th-hour help for a team that has been besieged by injuries and suspensions. The move looks worse when compared to rival Los Angeles, which acquired Irish star Robbie Keane in the same week that Zura came to San Jose.

Zura struggled while playing 20 minutes against the Galaxy just after arriving and didn’t make the trip to Toronto last weekend.

“It wasn’t like he was ever in there, and we thought we had something, so it doesn’t effect us at all,” Quakes star Chris Wondolowski said after practice during the team’s bye week.

Yallop also said the deal doesn’t hurt the squad but added, “If we wouldn’t have done anything and just” tried to sign a free transfer “the fans would have had a go at us.”

Doyle had combed South and Central America for players because leagues in the region were in season, leading to a better chance of getting a player immediately ready for action. Doyle said he had been assured Zura was fit but now believes he is nursing an undisclosed injury.

“It’s my fault 100 percent,” he said. “We’ve always been able to steady the ship with a few trades here and there. This year, we’ve tried to steady it, and it hasn’t steadied.”

And now the depleted lineup will be without midfielder Bobby Convey, who is suspended for the Chicago game Sept. 10 after getting his league-maximum fifth yellow card against Toronto FC.

After hosting Chicago, San Jose (5-10-11) plays five of its seven final regular-season games on the road, further decreasing odds it can qualify for the 10-team playoffs.

Contact Elliott Almond at 408-920-5865 and follow him on Twitter at http://twitter.com/elliottalmond.