Travis Ishikawa's role moving into 2015 is very unclear, given the signing of Norichika Aoki. The Giants, including Ishikawa, have 7 MLB ready outfielders (Aoki, Pagan, Pence, Blanco, Perez, Brown, Ishikawa) moving into spring training. Gary Brown is a bit of a wildcard, but he will most likely be making an MLB level impact by midseason, though he does have a months worth of experience in the show. Dismissing Brown for the time being, Aoki, Pagan, and Pence will be the starters on opening day, Blanco is penciled in as the 4th outfielder. Juan Perez is likely the giants 5th option because of his defensive prowess and speed. Ishikawa is 6th. Last. Last doesn't make the opening day roster, and he is certainly no longer needed to back up Brandon Belt at first on an everyday level, given that Posey can play 1st and Susac can suit up behind the dish, given Belt needs a day off.
Despite all of this, the Giants seem pretty committed to Ishikawa, having resigned him to rather large deal for a player of his caliber earlier this offseason. He hasn't been known to have much prowess as a pinch hitter, platoonman, or everyday player. But Brian Sabean hasn't completely forgotten how to do his job. Ishikawa has one advantage over other players that just can't be measured in statistics or sabermetrics.
Clutch. He is brilliant when the situation calls. The ability to keep calm and do what is necessary to help your team win. That is why the Giants like Travis Ishikawa. That is why I like him too. He is the ultimate in the Giants philosophy of chemistry, teamwork, and coming up big when it counts. He has no everyday position, and for that matter, no everyday role in particular, but he certainly has a role any day he is needed. Like Ryan Vogelsong. Like Jeremy Affeldt. That is why Travis Ishikawa is a necessity on the Giants 2015 roster.