From Ken Rosenthal:
Wolf keeping options open
Left-hander Randy Wolf preferred to return to southern California the last two times he was a free agent, signing with the Dodgers for the 2007 season and the Padres for '08. But Wolf is not limiting himself geographically in his latest stint on the open market, according to his agent, Arn Tellem — he is open to playing anywhere.
Wolf, 32, went 6-2 with a 3.57 ERA in 12 starts after getting traded from the Padres to the Astros last season, proving that he is again healthy. He might be a consideration for his original team, the Phillies, who are struggling to re-sign free-agent lefty Jamie Moyer. The Phillies, however, were miffed when Wolf spurned them after the '06 season.
I'm guessing Houston is not part of Wolf's desire to "play anywhere."