The Houston Astros have been shopping for a starting pitcher and a previously unlikely trade candidate has now officially jumped into the discussion: The San Diego Padres.

After their drastic overhaul this offseason, the Padres (43-49) have disappointed thus far and sit nine games behind the Los Angeles Dodgers for first place in the NL West and 6.5 games behind the Chicago Cubs for the second wild-card spot.

Trade rumors suggest the Padres will be sellers in some capacity before July 31, with most of the speculation surrounding high-priced pitchers James Shields and Craig Kimbrel as well as impending free agents Justin Upton, Ian Kennedy and Joaquin Benoit.

"One rival evaluator places the odds of Shields being dealt before July 31 anywhere from 75 to 90 percent, and he believes the Padres will move Kimbrel by the end of this month," ESPN Insider Buster Olney wrote on Saturday.

However, Shields and Kimbrel probably won't provide the Padres with an awfully profitable return because both are owed a lot of money throughout the remaining life of their contracts. It was noted the Astros were previously interested in some Padres' pitchers, but Shields and Kimbrel were not and still aren't a part of that group.

"The Cubs and Astros are among the many teams that could target the Padres' starting pitchers," FOX Sports' Ken Rosenthal reported last weekend. "Astros' manager A.J. Hinch previously worked in the Padres' front office. The Padres' Tyson Ross is under club control through 2017 and he would carry the most value of that group."

More was reported on this subject over the weekend.

"Sources told the Union-Tribune that the Padres and the Astros have held preliminary talks on starting pitchers, with right-handers Tyson Ross and Andrew Cashner believed to be among those mentioned," Dennis Lin of the San Diego Union-Tribune reported on Saturday. "There are no indications of anything imminent, and one source said the two sides had not spoken on the subject since early this month ...

"So far, however, discussions between San Diego and Houston appear to be a matter of diligence. The Astros are sorting through contingencies in the event that they don't land an elite pitcher such as Cueto. Meanwhile, the Padres realize they possess multiple attractive arms at a time when contending teams hope to add starting pitching."

The Astros are exploring top of the rotation options such as Cueto, Jeff Samardzija, Scott Kazmir and Cole Hamels (so far that's known) to pair Dallas Keuchel with another capable veteran. Ross or Cashner would be more of a depth acquisition given their lack of experience as full-time starters in the MLB (Ross has made 88 career starts and Cashner has made 69).

However, it's very possible Ross or Cashner become the Astros' primary option. There is a ton of interest in Cueto with the Toronto Blue Jays, Kansas City Royals, Los Angeles Dodgers, New York Yankees, Boston Red Sox and others hoping to contend potentially looking to acquire him. It's still unknown if Samardzija and Kazmir will be put up for sale, while rumors indicated Hamels would not accept a trade to Houston. All of these factors severely limit the Astros' ability to land a top arm, even though they have a stacked farm system and could provide another club with a good return.

There's less than two weeks until the trade deadline and the Astros remain one of the top teams to watch over that span.