The Giants top prospect, Brandon Belt, has earned an invite to Spring Training as a non-roster invitee and "could make this club" at the start of the year, according to Bruce Bochy. That is all well and good, but I have to believe that the chances of him making the team are slim at best.
The Giants have a history of being rather conservative with their prospects and bringing them up only after they have nothing left to prove in the minors. This is the way Brain Sabean handled both Buster Posey and Madison Bumgarner last season.
This conservative method also has an effect on the cost of the player to the team in the future. Delaying Posey a month and a half pushed his free agent clock back a year and I suspect that will be a contribution in keeping Belt down as well. By waiting to call up a player, a team can assure that the service time clock will be less than the required 172 days that comprise a major league season.
The major league season is usually in the 185-190 day range. Waiting until the middle or end of April will push back the free agent clock by one year. If Belt makes the team out of Spring Training, he would become a free agent before the 2017 season. If the Giants wait, like they did with Posey, they can push the free agent season until 2018 (he would almost certainly be a Super-2).
The big difference with Belt breaking camp with the Giants is that he becomes a free agent a season early, but the Giants enjoy his services for a full season instead of him missing the first month of the season. I don't know if this is the major deciding factor on when Belt joins the major leagues, but it has to be in the discussions and something that the Giants brass are weighing along with his performance.
As a fan, I want Belt now if he is ready. As a rational person doing analysis, I say wait a month so we can keep him under team control one more year.
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