I would say that Martin is better than both - but that's obviously the result of his career numbers, which are meaningless if Gibbons or Jacoby have spotted something in his swing that's keeping him from being effective. 4 games is not a "slump", right. But, like I said, if this four games plus the entirety of ST are enough for the coaches to see that Martin isn't entirely on point offensively, I'm fine with them making the decision to move him into a less crucial part of the order for the time being.
Pompey being in the 2-hole is the big story for me. Martin hitting *under* Navarro is a non-story, IMO. It's Gibby trying to break up the righties, really.
I unfortunately haven't had a chance to see many of the games so far this year (only the second two against the Yankees), so I don't think I have any particular insight into Martin's situation. What I'm really saying is that I like Gibby's willingness to tinker with this already strong lineup to try an eke out every advantage.