What on earth are the Diamondbacks thinking by promoting Yasmany Tomas?

A week and a half ago, Yasmany Tomas was not good enough to play in the Major Leagues for the Arizona Diamondbacks. Rather than give their outfielder and "third baseman" a spot on the roster, and a few starts a week spelling Jake Lamb, Mark Trumbo, and David Peralta, the Diamondbacks sent Tomas to Reno to play every day.

It was almost certainly the right call. Tomas is only 24 and last played meaningful baseball in 2013 in Cuba. When he was signed in the offseason for 6 years and $68 million, the Diamondbacks talked about moving him to third base. The reviews of his performance there in spring training ranged from "rough" to "laughable."

Tomas wasn't ready two weeks ago

Not that spring stats are terribly meaningful, but his .257/.307/.414 performance hardly screamed out that he was ready to face your Claytons Kershaw, Zacks Greinke, Madisons Bumgarner and Jameses Shields. At Reno, he hardly did anything to change that perception either. He hit just .190/.261/.381 in five games, with five strikeouts. He made only four plays in the outfield. There's absolutely nothing to indicate that Tomas is any more ready now than he was when Arizona broke camp.

And yet, here were the Diamondbacks yesterday, promoting the youngster. He's not filling in while someone is injured. He's not going to take anyone's spot. No, said General Manager Dave Stewart, "It's going to be challenging. We're bringing him here because we do need a player off the bench—a player that represents a threat—and then we'll use the other options as they come." See, the Diamondbacks feel like they won't need a 13^th pitcher (a laughable concept in and of itself) for a while, so they want another bench bat with some pop.

Instead of playing every day and improving his skills against MLB pitching, Tomas is primarily going to be called on when he's cold to face the best pitchers on the planet, most of whom he has never seen before. Astutely, Arizona manager Chip Hale anticipates some pushback, "Everybody is going to say he needs more at-bats, he needs to play every day. True, but there's something to coming here, getting a taste of what it's like to be in the Major Leagues, seeing how things work, being with the coaches here, and getting the game play ironed out.... There's a lot of things he can learn here while not having to worry about playing, you know, four or five at-bats a night."

Tomas can supposedly learn without 'having to worry about playing'

This is patently absurd. Even as I grant that there are parts of major league existence that a player can only learn once he is promoted, there is no substitute for getting the reps against pitchers for a young player after so much time off. Tomas may not have to worry about taking four of five at bats per night, but he will have to sit on the bench, poised to be called on at a moment's notice, probably in a pressure situation, at any point during the game. You tell me what sounds more relaxing: that or knowing you are going to get multiple reps, can carry lessons learned in one plate appearance over into another, and staying loose in the outfield when your team isn't hitting.

Tomas hasn't had time to learn anything new since Reno started playing last week, and anything he discovers about life in the big leagues while riding the pine isn't going to help him as much as figuring out how to handle triple-A-caliber velocity and movement (to say nothing of MLB-caliber velocity and movement). The Diamondbacks are sacrificing the long term development of one of their best prospects, in whom they made a ridiculously steep investment, to maybe get a couple extra hits between now and whenever they realize how stupid an idea this was to begin with.