In the beginning, the question was phrased as to which player someone should select in a keeper fantasy league, a Strat-O-Matic baseball league or who you would want if you were starting a franchise today.
When you have two players the caliber of Posey and Heyward, I don't think that you can really go wrong going with either one of them. Both players got their respective teams to the playoffs (on teams that were not in the playoffs the previous year).
Last year's crop of rookies has been described by Tim Kurkjian as "the best group of rookies in MLB in over the past 25 years," so to go with either one of these guys, I do not think you can let the selection of Rookie of the Year sway your decision.
One thing that has to be considered when making your decision is the fact that Posey is a catcher. Finding a top-notch offensive catcher is extremely difficult. If you do find one, most players that are offensive catchers tend to lack the defensive skill sets. Not Posey. Posey showed that he can handle a staff, make all the throws and have excellent footwork necessary for throwing and blocking, and most of all, he showed that he can lead.
Though Posey does take a slight nose up on Heyward because of the position he plays, Heyward gains ground back because of his age. The difference in starting the season at 21 and 24 is considerable. Neither one is an aged veteran that is on the downside of his career, but at the same time, Posey was playing college baseball at the same age that Heyward will be when the season starts.
Additionally, Heyward is not a Manny Ramirez-type outfielder either. Heyward is more than capable of fielding his position, and he is slowly being considered one of the best right fielders in the game.
When you look at this matchup, there are so many little things that could favor either one of these guys to help you make a logical selection. In the end, when I decided to make a decision, the man in the picture above for me is Jason Heyward.
I believe that Jason Heyward is a once in a generation player. If he is able to command the strike zone as well as he did at 20 years old, then I would love to see him once he becomes more seasoned. I think one of the most impressive stats from Heyward's stat sheet is the .391 on-base percentage. That average placed Heyward as the fourth best OBP in the NL and the eighth best OBP in MLB—all at 20 years old.
Heyward has a body frame that places him in a category that could put him in the upper echelon of the elite players in the game. Standing 6'5" and weighing 245 lbs., Heyward still has room to grow in his skinny frame. With the increase in size and the experience facing top of the line MLB pitching, Heyward's power potential is enormous.
Add the power potential of Heyward to his speed and then calculate his incredible eye and arm strength, and you have a true five-tool player. Heyward's speed receives a great injustice if you just look at his stolen base statistics (11 last year). Bobby Cox is infamous for not using a running game as one of his offensive strategies. But watching Heyward cover the outfield like a deer and go from first to home on a hit in the gap, you see game-changing speed.
Yes, Buster Posey is incredible. Of course I would take him on my team in a heartbeat. But given the upside of Heyward and how he could redefine the five-tool player...in this debate on which player to take, I have to agree with MLB.com's 2010 prospect ratings and say, "Heyward is No. 1!"