In fairness, Doug didn't state, "Trey would be back." Doug was speaking to the O-Line next year and included Trey Smith saying he will most likely play OG next season. Doug also said the C and OG positions are more important in college football than the tackles unless your offense passes a lot such as Washington. (I think Washington was the example he used but it may have been Washington State.)
I took it as more of a, Trey is part of the team until/if we are told he is no longer part of the team.