The only piece of criteria I could find for the "Comeback Player of the Year" was "re-emerged on the baseball field during a given season." From that alone, that could mean anything. You could argue that a player who went to the dugout for a pee then came back and made a good play could win it, cause he "re-emerged" in the most literal sense. Also the writer who voted with this logic's house would justifiably be engulfed in rolls of toilet paper. But looking through past winners there seems to be two categories:
1, Got hurt, then healed, as the human body does, and did well.
2. Was bad, then good again. Helps if they were at least kinda good before the bad.
Riding on the second category, Jean Segura has a good a case anyone in the National League. After riding two good months in 2013 into an All-Star appearance in Milwaukee, his playing career fell of a metaphorical cliff. Segura's 2013 season got him a slash line of .294/.329/.423 with 12 home runs. His next two seasons *combined* produced .252/.285/.331 11 dingers.
In 2014, Segura experienced one of the worst tragedies one can even fathom, losing his 9-month old son. He also suffered a DL stint due to Snakepit Favorite Ryan Braun hitting him with a bat in the dugout that season. Between all of that and his numbers not coming close to 2013, you'd probably be correct in assuming that Jean Segura would become one of those journeyman infielders that hopped from team to team once his years of control with the Brewers were up. You'd randomly look him up on Baseball Reference and be like "Wow, that guy was an All-Star once?"
Then, of course, Dave Stewart happened. Considering all of his other, uh, follies, it can be hard to imagine that this was prescient thinking on his part. But damn if it hasn't worked out in at least the short term. Segura is on pace to set career highs in all three slash categories, Home Runs, RBI, and has already set a career high for Walks in a season with a month left. And all it apparently took was a flight out of Milwaukee and a new swing, which lowered his hands so he could get more under balls and get fewer groundouts than he had been getting, seems to have revitalized him. He's second only to Paul Goldschmidt in bWAR on this year's team.
Of course, there are always concerns about sustainability, and there's the nagging thought that Isan Diaz will eventually be some sort of monster once he gets to the majors with not-us. However, in the present, Jean Segura has been a bright spot in what has been a bit of a bummer for the Diamondbacks this year. It's easy to get swept up in seeing a potential lineup with him, A.J. Pollock, Goldy, Jake Lamb, and other guys operating at full potential. (None of them can pitch, which doesn't solve the more immediate problem, but that's neither here nor there.)
To come back to Comeback Player of the Year (ha ha wordplay), I feel like Segura stacks up really well to win that award. It wouldn't automatically fix everything wrong organizationally with the Diamondbacks, but darn it if it wouldn't be cool and make us feel happy for a little bit.
Is he going to win it? That's another story. Jose Fernandez has come back strong from injury, and he's more of a household name. I can't begin to fathom the thought processes among the people who vote on this. However, you wouldn't look like a guy sitting outside the Burger King with a tinfoil hat yelling at cars if you suggested Segura had an extremely strong case. His positive contributions to this Joy Division song lyric of a Diamondback's season should be lauded.