With Ludwick questionable to return, the farm system devoid of MLB ready OF talent and the Free Agent market either being expensive (Hamilton, Bourn, Swisher, Upton) or underwhelming (most everyone else) the next option would be to explore the trade market. Here are some guys I see as possible and plausible trade targets:
Michael Morse, Nationals: With Werth and Harper entrenched in their spots and Washington being rumored to pursue Bourn and Upton, that leaves Morse without a spot (especially considering they have Tyler Moore, who is 5 year younger version of Morse). He hits for power and average and he'll never be confused for Mike Trout in the field but could be had without gutting your minor league system. With the rumored interest in Bourn and Upton, maybe they would have interest in Stubbs as part of the package although that's probably just wishful thinking
Gerrardo Parra/Jason Kubel, Diamondbacks: The Diamondbacks would like to have Adam Eaton in CF full time in 2013 leaving them with 5 guys for 3 spots. Upton, Parra, Kubel, Young and Eaton. They will try to get rid of Young and will listen on Upton but they would have to eat significant money on Young and Upton will be expensive. Parra is excellent defensively and can play all 3 OF spots, is decent with the bat and is only 25 years old and under team control through 2015. Kubel tailed off after a flaming hot start to the season but still ended with 30 HR and an OPS of .833 and is owed $8.5M on a rental or $15M over 2 years. Again, not great in the field and doesn't hit lefties well at all but gives you power
Denard Span, Twins: This was rumored at the deadline but never came to fruition and he is expendable with Ben Revere and Joe Benson waiting in the wings. He's signed under a team friendly contract and can leadoff and play CF. A Hamilton/Span top of the order would get speed and on base ability in front of Votto and the outfield would certainly be covered. He probably won't come cheap, but again, you wouldn't have to gut the farm system to get him.
Dexter Fowler/Eric Young, Rockies: With CarGo in Left and Cuddyer in Right, there are 2 guys for 1 spot in Center for the Rockies. Both are switch hitters who are great on base guys. Young has better base stealing ability but both are great defensively and under team control until at least 2015. Either one would look great in Center and slide over to Left once Hamilton is ready.
Chase Headley, Padres: This would be buying high, so he would probably be too expensive for what you'd be getting. Frazier would be moved to left and Headley would be a great upgrade to the lineup. Again though, at what cost?
Mike Olt, Rangers: Olt is a highly regarded prospect, so he would probably be expensive, but he's blocked by Beltre. He could take over for Mitch Moreland at 1B so he may not even be available but it would be worth asking.
Obviously, this is a rough list, so I'm sure I missed some but just thought I would get a discussion started.