CB - look for Joel Matip, Bassong, Kolo Toure (he's supposed to be TL-ed by that time), Nedum Onuoha (he can play CB, Central Defender Cover), Mateo Musacchio (if you can get him) or his teammate Gonzalo Rodriguez, maybe if you can snap up Nicolas N'Koulou?
MC - hmm Milan Badelj? Stephen Appiah? Sulley Muntari (loan), Jadson, Guarin, Jucilei, Elias, Christian Romaric, Michael Bradley?
ST - Err Bafetimbi Gomis? Lucas Gaucho, Christian Benitez, Fatos Beciraj (pretty good poacher actually), Saviola (I think he still plays), Al-Qahtani, Altidore, Fred (Fluminense)... Maybe even some of the old guys like at that time PEtric, Van Nistelrooy, Shevchenko (if some of them are still playing)
Not sure about the price tags tho, but Gomis could be available to you even on free (on a few of my saves when he nears the end of his contract in like 2013, he doesn't want to renew it with Lyon)