They HAVE to be a focal part of the offense if San Antonio is going to beat the Sonics.
In the playoffs so far the magic number appears to be 39.
When Parker and Ginobili combine to score 39 or more points the Spurs are 5-0. Their combined 27 points in the last game was their lowest combined total and the 101-89 loss to the Sonics was the Spurs worst loss of the post season.
Everything Tim brings to the table matters, and the other players' contributions fill in all of the gaps, but the key to the playoffs will be the play of Tony and Manu.