LA Times is reporting that the strike threat has Hollywood on edge as the countdown continues to June 30th when all SAG actors are likely to strike as talks between SAG leadership and the studios have failed to reach an agreement.
SAG has granted waivers to 350 independent films (those made outside the studio system) but major studio projects have not been granted waivers as a result this directly impacts Transformers: Revenge of the Fallen which has built-in hiatus to plan for the event. The length of this hiatus is not known and if the strikes goes past the planned schedule that could prevent the movie from meeting its release date.
So to sum, SAG doesn’t appear close to an agreement. If a strike occurs it will likely start July 8th or shortly after. Transformers 2 production is already shut down and when they return is unknown. The impact on current and future projects will pretty much be immediate.
Source: Transformers Live Action Movie Blog