Either that... or what Phil Wood said was true... and that Rizzo wants Stairs on the roster... so Johnson wanted to at least give him some work if he's going to be stuck with him.
If Stairs can't DH, then he has no business being on the team. Obviously, I think he is done and shouldn't be on the team, but this is the time when it makes sense to give him a game or two with multiple PAs to convince everyone involved that he's done. These lineups are organizational decisions not simply based on the whim of the manager.
The only real issue I had with Davey last night was leaving Lannan in, but that's a pure judgement call. At some point, you have to stop coddling the pitchers and let them battle through situations and show what they can do. Lannan only gave up singles the whole game, and he was getting groudn balls that were getting through. I can see the coaches thinking that he had just as good a chance of getting an out. Personally, I would have taken him out at least two batters before. I'm not a fan of HRod, but again, the organization seems to want to give him as much work as possible and is committed to letting him develop. In the end, while I can't stand having his control problems on the mound, he ended up being effective over several innings and in a game that went to the 10th inning, we only used 4 pitchers.
I remember being at a game in the late 90s when Davey went to the bullpen for a rookie debut very early in the game when the team got behind. It seemed he was content to concede the game in order to preserve arms for the next series. I'll never be that surprised by his decisions because he manages for the season not for a game. The difference between Riggleman and Johnson is that Johnson has earned the benefit of the doubt. Riggleman has earned the doubt.
I suspect for the near term, Davey will be doing some things based on the Rizzo directives and the input of the coaches. His strength will be with the players in the clubhouse and the overall development not necessarily the in-game moves. A big priority he should have at this point is to work with Eckstein to get Werth sorted out. That's a big black hole right now.
As frustrating as last night's game was, the flipside from Riggleman would have been no bench left and 6 pitchers burned by the end of that game.