Zebra Grass in 'Critical Condition' ????

This year I planted 4 dwarf zebra grass plants in containers on my back patio. They were all 4 doing great and looked fantastic. Tonight I noticed that one looks like it didn't get enough water - it's dry and the blades are closed up and much "skinner" than the others. I'd hate to lose one and am curious if this is a sign of too little water. It's strange because I think it's been given as much water as the other 3 - all of which look fine.

Do you have any suggestions for ways to "revive" this poor fellow - other than increased watering?

Thanks.