The Padres are looking into bringing back Pedro Astacio, the veteran pitcher who excelled for them down the stretch last year. There is a catch: Because Astacio and the Padres failed to reach terms by a January deadline, Astacio couldn't join the Padres until May 1. Any other club could offer Astacio the chance to open the season on its roster. But so far, Astacio, 36, has remained unsigned and his agent, Steve Schneider, said yesterday the Padres are among those interested in signing the right-hander. ?Anything is possible, including San Diego,? Schneider said. ?It would not be uncomplicated ? but it's not impossible.? The Padres recently stated their case for Astacio, who has been training in the Dominican Republic. ?We have had discussions,? General Manager Kevin Towers said. ?Other than that we're not going to comment on the negotiations.? The Padres could sign Astacio to a Triple-A contract with an assurance ? but not a contractual guarantee ? that he would be the first to join their rotation after April 30.