This has been the most disappointing season record-wise Gregg Popovich has had in his long tenure with the Spurs. 
Lately, though, the Spurs have show more life going 7-4. The Spurs defeated the Thunder, 121-112, at home back on Nov. 7 when they weren't playing nearly as well. 
The Thunder have failed to cover the last six times they've played at San Antonio. 
Oklahoma City is coming off a 1-point road win against the Raptors and a 5-point home win against the Mavericks. The Thunder are a season-best three games above .500. Oklahoma City isn't that good. This is the time to step in against them in this difficult road setting and in a crucial matchup for the Spurs.
The Spurs are 14-18. Following this game, the Spurs play an away/home series against the Bucks and a road game versus the Celtics. They are going to be underdogs in each of those three contests. So this becomes a high priority game for the Spurs putting them in must-win mode.