San Diego ? San Francisco closer Robb Nen has a strained throwing shoulder and expects to be out for 2-to-3 weeks.

Nen said he was relieved the news wasn’t any worse after being examined Tuesday by Dr. Lewis Yocum, who performed arthroscopic surgery on the reliever’s right shoulder on Nov. 8.

“It’s a lot better than what it could have been,” Nen said Tuesday night. “I could have torn something or done something else.”

Nen was placed on the 15-day disabled list prior to Monday’s season opener, retroactive to Sunday.

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Martinez waiting: Three-time Cy Young Award winner Pedro Martinez has extended the opening-day deadline he gave Boston to sign him to a contract extension. The right-hander said in February that unless the Red Sox exercised his $17.5 million option for 2004 or signed him to an extension by the end of spring training, that he likely would finish his career elsewhere.

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Union may accept plan: Baseball players might accept, at least on a trial basis, management’s plan to give home-field advantage in the World Series to the league that wins the All-Star game.

Owners approved the proposal Jan. 17, and union lawyers have discussed it with players for 2 1/2 months. The union’s executive board holds a telephone conference call today.

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Astros honor Columbia crew: In a ceremony filled with tears and emotional songs, the seven astronauts who died in February aboard space shuttle Columbia were honored Tuesday by the Houston Astros before the start of the team’s season opener.

Children of Columbia’s crew simultaneously threw ceremonial first pitches before the start of the Astros’ game against the Colorado Rockies at Minute Maid Park.