At the MLB season's halfway point, and in the wake of the deadline to sign draftees, I put together an update of the top 50 prospects in baseball, given that a number of players from my top 100 rankings, which came out in January, have graduated to the majors.

In ranking these players, I tend to weigh upside or ceiling more heavily than proximity to the majors. The list includes a mixture of players as high as Double-A or Triple-A as well as a few who signed in recent weeks who have yet to make their professional debuts.

Players who have already passed the cutoff for rookie of the year eligibility are not included here, nor anyone currently on a major league roster.

Note: I use the 20-80 grading scale in these comments to avoid overuse of the terms "average" and "above average" across the player comments. On that scale, a grade of 50 equals major league average, 55 is above average, 60 is plus, 45 is fringe or below average, and so on.

1. Kris Bryant, 3B | Chicago Cubs

Age: 22 | Current Level: Triple-A (Iowa)

Preseason Ranking: 15

While there are players in the minors who offer higher ceilings -- notably the next two guys on this list -- Bryant is so close to major league ready that his value at this moment is at least as high as that of Buxton, who's playing now but has been hurt most of the year, or Correa, who's out at least until the Fall League. Bryant has power, he's capable at third base, and his eye and approach continue to improve. Even if he's just a .260 to .270 hitter -- probably a pessimistic forecast -- he'll still be an MVP-caliber bat who hits 30-40 homers and gets on base at a solid clip.

2. Byron Buxton, CF | Minnesota Twins

Age: 20 | Current Level: High A (Fort Myers)

Preseason Ranking: 1

It's been a rough year for Buxton, who missed almost three months with a pair of injuries that not only cost him development time but also left him rusty, even as he repeats high-A. Buxton's injury might push back his timetable, but I don't think it will change his ultimate ceiling at all; he remains an 80 runner with an 80 arm in center field, the right mix for a plus-plus defender. He has the bat speed and swing to hit for average and some power. If you want to yell and scream that he's really the best prospect in baseball -- instead of Bryant -- I won't put up much of a fight. I'd gladly take either guy in my system.