Happened to me as well a few times with an AMD card. Probably a bug.
Confirming your claim the game looks a PS2 game in close ups. It's incredible. It's like a roller coaster of low and high quality graphics when playing Rage.
It was so shocking that I took even a few screenshots with Xfire when playing:
http://www.xfire.com/profile/megadupek/screenshots/rage/?view#118671346
http://www.xfire.com/profile/megadupek/screenshots/rage/?view#118671312
http://www.xfire.com/profile/megadupek/screenshots/rage/?view#118671294
... even if id Software is going to release the uncompressed pack with 75GB that won't help as it seems that the textures are just like that ... but there is hope. The ingenious (and I don't mean that ironic) father of the Rage engine has a plan:
http://twitter.com/#%21/ID_AA_Carmack/status/124916837791186945
Carmack: "We have a bicubic-upsample+detail texture option for the next PC patch that will help alleviate the blurry textures in Rage."
From what I understand the textures will get softer like shown here: http://www.cse.cuhk.edu.hk/~leojia/projects/upsampling/index.html
... but then will get some grain via a detail texture: http://wiki.splashdamage.com/index.php/Detail_Textures