Recap: Astros 7, Rockies 3
Matsui was batting .141 this season and was hitless in his last 20 at-bats. The 34-year-old Matsui was in the last season of a three-year, $16.5 million contract that he signed in December 2007.
Matsui did not play in Wednesday's game, but thanked the Astros for his tenure here afterward.
"I could be on a great team with great fans, and I could play in an environment with good teammates and good fans in a good city," he said through a translator. "I had a really good time and it was my pleasure."
Matsui said he had not considered the possibility of continuing his career in Japan.
"I'm just going to keep myself doing exercise and keep my body fresh," he said. "I cannot think about it right now."
Houston will replace him with infielder Oswaldo Navarro, whose contract the Astros purchased from Triple-A Round Rock. General manager Ed Wade says the transaction will officially go into effect on Thursday. By rule, if Matsui is not claimed by another club by Monday, he will become an unrestricted free agent.
Matsui hit .293 in his first season with Houston, but was plagued by injuries overall in his time here, going on the disabled list four times.
"This year, and for parts of last year, his performance hasn't been quite what we expected or what we saw when hit .293 in 2008 for us," Wade said. "Last year, a succession of back issues came up from time to time, and then this year was certainly a significant struggle for him."
Wade said before the game that he was considering lineup changes to kick-start the Astros' slumping offense. Houston matched a season-high 13 hits on Wednesday night, but came in with the worst team batting average (.227), run total (115) and home run total (20) in the majors.
"Perhaps if we were firing on all cylinders at other positions, this would be something that we would have sort of pushed to the back burner," Wade said. "But we felt that it was important to do it at this time."
Navarro, 25, was hitting .312 with four doubles, one triple, three home runs and 19 RBI in 20 games with Round Rock. He has appeared in 14 games at shortstop and seven at second base. Navarro signed a minor-league contract last December and appeared in 11 games at spring training.