Even if Rivera and Kendall were to have exact same BA and OBP, there seem to have been several (many?) occassions over the past year when Kendall has come up late in a game when we need a chance for an extra-base hit or even just a sac fly. Rivera has a better chance to do this than Kendall. I like Kendall just fine - I think he has made a nice contribution to the team, especially behind the plate - but he has trouble just advancing a runner, since he typically either chops to third or pops to shallow right/first base. The disadvantages of putting Rivera in to PH would be a) experience in pressure situations, b) lack of speed if he does get on, and c) I would guess that he will K more than Kendall.