Injuries, injuries, injuries! It was obvious to me that Larnach wasn't right when he came back from his first stint on the IL and the results panned that out. The Larnach we saw before he was injured is at least a solid MLB player and perhaps much more. There is swing and miss in his game and there will be slumps, but there is excellent power and good defense. He takes his walks, as well.
To the original question, it is really tough to count on any player who isn't established (Larnach, Kirilloff, Lewis) and coming off injury. My thought is that there needs to be enough depth if one or even two guys fail due to injury or ineffectiveness that there is someone to replace them. Having Gordon produce and stay healthy this year provides much of the desired depth. Arraez, Miranda, Kirilloff, Gordon, Lewis and Larnach provide a lot of positional flexibility.
I also have not been swayed by Celestino. He's a competent center fielder, but his offense and base running aren't major league quality. With Buxton's injury history, he needs to stay on the roster, but I don't think he should be guaranteed a major league job next spring.