Assuming the Rangers don't score 10 runs in the final 4 innings of tonight's game (while holding the Yanks scoreless), Texas will be 10-16.
There are 28 games remaining in May. If the Rangers go 16-12 over that span, they will be 26-28, two games below .500.
I think that's the dividing line. At 26-28, assuming that the Angels aren't en fuego in May, the team is probably close enough that you can drink the Kool-Aid and say that the team can still contend.
At 25-29, though...you are 4 games under .500 two months into the season. You probably have to start making calls to try to determine what the market is for Kenny Lofton, for Eric Gagne, for Sammy Sosa, for Brad Wilkerson. And for Mark Teixeira.
This team is playing horribly right now. The team is better than they have shown, but if they can't get it in gear, that doesn't really matter. If the Rangers play poorly enough in the first two months to put themselves out of contention, it is moot.
The Rangers need 16 wins between now and the end of May.
And if they don't get those 16 wins, the highlight of the summer is going to be seeing how much the Rangers can get in exchange for Teixeira.