Oswalt has openly said, according to Jon Heyman, he'll stay in shape and look to join a contender midway through the season; he's also said that, although willing to go anywhere for the right price, he prefers to be in the South or Midwest.
Let's take a look at teams that are still connected to Oswalt and teams that may have an interest in him later in the season.
One team that has been heavily linked to Oswalt this winter is the Los Angeles Angels of Anaheim. Although they have a strong pitching staff, which includes Dan Haren and Jered Weaver, the Angels interest in Oswalt is for the back part of their rotation in order to add pitching depth.
As with some of the other teams on this list, the Angels fall out of Oswalt's zone and, thus, they would likely have to pay a higher salary to entice him west. Is he worth it? Right now the Angels don't seem to think so, but anything is possible in the heat of a division race.
Much like the other teams interested in Oswalt, the Boston Red Sox are interested in Roy to add pitching depth to, what seems to be, a very shallow pitching rotation. Beyond Jon Lester and Josh Beckett, the Red Sox are unsure what to expect from their rotation.
Again, much like the Angels, the Red Sox do not play in the South or Midwest and, thus, would have to entice Oswalt with money.
The St. Louis Cardinals are another team that has been linked to Oswalt but, unlike the previous two teams listed, they do reside in the area he is willing to play. The defending world champs could have a nice leg up for Oswalt's services but, oh wait, here comes another team that could interest Oswalt...
The Texas Rangers could be a problem for the St. Louis Cardinals when it comes to acquiring Roy Oswalt. The Rangers certainly fit all the preferences Oswalt has stated, and with Feliz's shoulder there could be an opening in their rotation.
The New York Yankees are always looking to improve, especially in a simple way by just paying a player rather than having to give up a player. That said, their rotation is a bit uncertain now with Pineda's injury. Sure, Andy Pettitte came out of retirement but who knows if he is still effective.
The Yankees will almost certainly keep tabs on Oswalt, especially as the season goes on—if for no other reason than to drive up the price on other teams they are competing with like the Angels, Rangers and Red Sox (all teams that have been in on Oswalt as well).