What will Gregg Popovich do?

Well, you can't say the Spurs haven't faced this situation before. They left home up 2-0 and came back tied at 2-2, just like they did five times between 2003 and 2006. Throw in the four other situations in the Tim Duncan era in which the Spurs were tied in a series after four games -- the last time against New Orleans in 2008 -- and they're mighty familiar with this drill.

It's one that calls for adjustments, and historically Gregg Popovich has kept what might be called a "universal adjustment" in his pocket. If things are going badly, he changes Manu Ginobili from starter to bench, or from bench to starter.

The particulars of the series haven't mattered; it has been a move he's always made to shake up his rotation and give the opponent a different look, to the point that both Popovich and Ginobili joke about it.

And it's time again.

Coming into this series, it appeared the Thunder, not the Spurs, were the ones who could benefit from starting their sixth man, because it would let defensive ace Thabo Sefolosha match up against Ginobili.

But they've found success with Sefolosha on Tony Parker and Russell Westbrook on Danny Green, a matchup that won't work out nearly as well if Ginobili is in the starting lineup. Westbrook will be forced back on to Parker, with Sefolosha checking Ginobili, and the Thunder's rotating defenders will respect Ginobili's threat off the ball a lot more than Green's.

Additionally, such a move offers an opportunity for Popovich to tighten his rotation. For starters, Green isn't giving him much -- he's 4-of-21 on 3-pointers and hasn't drawn a foul --- and one wonders if Popovich won't shift major chunks of his playing time to the more effective Stephen Jackson.

It also helps increase Ginobili's playing time. First, the Spurs aren't forced to play him in stints of 17 consecutive minutes, which is a challenge at this point in Ginobili's career. They tried it in Game 1 to great effect, but in the three games afterward he averaged only 24 minutes -- far too little for a player of this caliber. (Ginobili fouled out in Game 4, but only after an intentional take in the last minute.)

But the biggest reason to start Ginobili might also be the simplest: What the Spurs are doing right now isn't working. They were supposed to have the big advantage in depth behind their three stars, but it's tough to find supporting evidence for that right now. Duncan is a plus-6 and Parker is a plus-10 for the series, but the Spurs are getting rolled when those two are off the floor.

Starting Ginobili, alas, is only part of the solution. The rest of it has to come from the frontcourt, where the Spurs remain searching for combinations that work.

The most perplexing piece of that puzzle has been the near-total disappearance of Matt Bonner. Understand that in the regular season the Ginobili-Bonner combination was the most potent one in the league, helping the Spurs' bench destroy most opponents. The Spurs played 382 minutes with that combo and had an off-the-charts offensive efficiency of 126.3, according to NBA.com's advanced stats too. That stat appears to be the best of any pairing in the league this season that played reasonably often.

Suffice it to say it hasn't worked out that way against the Thunder, or in the playoffs in general. With the Thunder focused on running him off the 3-point line, Bonner has played 53 minutes and scored one basket; he's a minus-22 for the series. Meanwhile, the two Spurs with the worst on-court offensive rating in the playoffs are, you guessed it, Ginobili and Bonner.

Taking Bonner out of the rotation is harder than it looks, however, because it entails a wholesale reshuffling of the Spurs' frontcourt deck; San Antonio's frontcourt combos don't work especially well unless one player is a shooter, with the exception of the DeJuan Blair-Duncan pairing.

Popovich went to Blair in the second half of Game 4 and didn't play Bonner or Tiago Splitter at all, and that could be one part of the solution. Blair also had a strong stint in the second half of Game 3 and had a 22-point, 11-rebound outburst against the Thunder in the regular season. However, he didn't play well in the other two games against Oklahoma City.

Moreover, San Antonio's much greater issue is on the other side of the ball, where Blair is a liability. The Spurs have yet to stop the Thunder's offense; they won the first two games by scoring at a ridiculously high rate, but for the series they're surrendering 110.8 points per possession, and that figure has been consistent from game to game. Blair's best skill, rebounding, hasn't been the problem. It's the initial shot that is burning San Antonio: The Thunder are shooting 52.8 percent on 2s and getting to the line with regularity.

Bench units, in particular, have been just destroying the Spurs, and this may be the best case for starting Blair: It puts a better defender, Boris Diaw, with the second group. Add Green to that unit for defense on James Harden, and perhaps the Spurs can shake things up enough to pull the series back in their favor.

Or maybe not. By this point, we're talking about some fairly wholesale changes for a team that is tied 2-2 with home-court advantage and is 72 hours removed from a 20-game winning streak. Starting Ginobili and Blair and banishing Bonner and bringing Diaw and Green off the bench -- it starts sounding a bit rash to do all of that, but you can make a strong case to pursue each individually. You could make just as strong a case to start Jackson and bring Kawhi Leonard off the pine as the backup 4, for that matter.

This is partly because of San Antonio's tremendous depth, which puts a lot more options in play. The Thunder, in contrast, basically have had one major question the whole series -- play big or play small -- and otherwise gone with a well-defined eight-man rotation.

But also, it's because a lot of the things that have worked all year for the Spurs haven't in this series, even when they were winning Games 1 and 2.

History says they're still in a pretty good spot. In series in which the home team wins the first four games, as has happened in both conference finals, the team with home-court advantage has won 39 of 47 times since the ABA-NBA merger. However, when the home-court team was outscored in the first four games -- as the Spurs were -- the odds shift to a less heartening 14-8 record. (Miami, in contrast, is in pretty good shape. Home-court teams that outscored their opponent in this situation, as the Heat have, are 25-1.)

We keep waiting for Popovich to pull out that magic adjustment to tilt the series back in his favor, and it hasn't happened yet. Perhaps Scott Brooks just has better cards; he also quietly has played his hand extremely well the past three games.

We don't know exactly what Popovich will do, but I'd expect that Ginobili-Bonner combo to be at the heart of it. Shifting at least one of those rotations may be enough to switch the dynamic back in San Antonio's favor.

Statistical support provided by NBA.com