Davey is a brilliant baseball man. A lot of managers would have coddled Harper and benched him. He pushed the kid and succeeded. And it would have been the right move even if he went O for 5.

Harper so far in Sept. .375/.468/.725 with more walks than K's.

Man...there is just so much awesome young talent in the bigs right now. Machado, Harper, Trout, Profar. Has there ever been this sort of influx of teenagers? Probably hard to quantify.

Harper is now officially the highest ranking 19 year old position player in MLB history in rWAR, though he is still nearly a full win behind Ott in fWAR, which seems like a pretty significant discrepancy.

So you're saying that Selig's genius idea of steroid-infused fruit loops is finally paying off?

He is so much ####### fun to watch. I feel really lucky to have moved back to D.C. in 2008 to get to enjoy the whole process.

i saw his MLB debut!

Is there a way to quantify WAR by age in a single season? So, seasons ranked by the most WAR accumulated by 19-20 year-olds in that season?

Is it safe to say that Harper has elbowed his way back into the NL Rookie of the Year discussion with his late-season resurgence?

Is there a way to quantify WAR by age in a single season? So, seasons ranked by the most WAR accumulated by 19-20 year-olds in that season?

Fangraphs stat leader tool with filtering is here.

B-R stat leader tool with filtering is here.

Note that some of the info on Baseball-Reference may be hidden without a premium membership.

Is there a way to quantify WAR by age in a single season? So, seasons ranked by the most WAR accumulated by 19-20 year-olds in that season?

he's #1 among 19 year olds

Edgar Renteria?!

I never would have guessed that guy would have been in the top 5 list.

[10, 11] What I meant was combined WAR by all 19 and 20-year-olds in a given season and then ordering the seasons in descending order.

What I meant was combined WAR by all 19 and 20-year-olds in a given season and then ordering the seasons in descending order.

the only year in which there were more than one 19 year old with >0 WAR was 1964 with Kranepool (0.9) and Tony C (1.4), so Harper wins by his own self

if you add together contributions from both 19 and 20 year olds, then this season is #1, although 1996 is pretty close (Arod and Renteria)

Quite the list for 19 year olds - just 6 qualify but all 4 retired ones are in the HOF, Renteria is in his age 34 season with 2327 hits mainly as a shortstop and 5 ASG thus has an outside shot at the HOF (needs to become a regular again and get over 2500 hits I'd think), and Bryce Harper. With Harper having the best score for the group at 19. Wow.

I was surprised by the asbence of Tony C, but I guess he was a shitty defender, according to baseball reference.

I'm inclined to believe that Renteria is older than listed. He had one of the greatest seasons a "19-year old" has ever had, follows it up with a few more AS seasons, but is basically burnt toast by 32?

I'm inclined to believe that Renteria is older than listed. He had one of the greatest seasons a "19-year old" has ever had, follows it up with a few more AS seasons, but is basically burnt toast by 32?

The rumor was just the opposite.

You mean he was supposedly 17 or 18 in his rookie year?

You mean he was supposedly 17 or 18 in his rookie year?

The Miami Herald reported back in 1997/1998 or so that he was a year younger than his birth certificate (it's really hard to find the exact article now, sadly) and that the Marlins had skirted the rules so that they could sign him at 15 rather than 16. MLB didn't really get tough with this thing until it came out that Betemit was 14 when he signed.

Hypothetical: Would you rather have Harper and Strasburg or Trout?

Harper and Strasburg and I wouldn't have to think about it. Am I crazy?

Harper and Strasburg anyday.

I'd probably take Harper over Trout straight up.

Renteria is in his age 34 season

You're looking at his 2011 line. Renteria is no longer playing.

BBref has already made the adjustment to the 1976 birthdate. Other sites give him the 1975 birthdate and that's the birthdate he was signed under.

BBref has already made the adjustment to the 1976 birthdate. Other sites give him the 1975 birthdate and that's the birthdate he was signed under.

I wasn't sure about that, in the back of my mind, I thought I had read that the adjustment was made, but couldn't remember for sure. Just wanted to point out, that it is probably unlikely that he was older than his listed age.

Is it safe to say that Harper has elbowed his way back into the NL Rookie of the Year discussion with his late-season resurgence?

Absolutely. He's #2 at worst, with his only real competition being Wade Miley. Probably Harper will take it considering the difference in recognition between the two.

Huh - didn't notice Renteria didn't play this year. A bit surprised as I've been watching the Jays use Omar Vizquel this year and I'd figure Renteria would be significantly better (OK, most AAA guys and a lot of AA would be better). Maybe he just wanted a full time or nothing type situation and ended up with nothing. Still, when he is as bad as it gets for that group you know it is a nice group to be part of.

I should have noted that the list in #11 is for position players. There are actually more 19 year old pitchers with >3 WAR. (Gary Nolan?! Seriously?)

What I meant was combined WAR by all 19 and 20-year-olds in a given season and then ordering the seasons in descending order.

These are the ten-best seasons for total WAR by players 20 and under, post-integration. (I set min WAR at 0, so no seasons get penalized for having young players perform poorly.)

17.5 - 1959 (Vada Pinson, Jerry Walker, Bob Miller)
17.5 - 1971 (Bert Blyleven, Don Gullett, Cesar Cedeno, Greg Luzinski)
15.8 - 1957 (Don Drysdale, Bill Mazeroski, Dick Drott)
15.6 - 1985 (Dwight Gooden, Jose Rijo)
14.9 - 2012 (Mike Trout, Bryce Harper)
14.3 - 1996 (Alex Rodriguez, Edgar Renteria, Luis Castillo)
13.2 - 1975 (Dennis Eckersley, Claudell Washinton, Rick Manning)
12.9 - 2010 (Jason Heyward, Mike Stanton, Madison Bumgarner, Starlin Castro)
11.8 - 1955 (Al Kaline, Pedro Ramos)
11.4 - 1974 (Frank Tanana, Robin Yount, Dennis Blair)

This is a somewhat problematic method - 1959 and 1971 rate at the top not so much because lots of great young players debuted, but more because for some reason tons of unimpressive kids got playing time and got 0.4 WAR apiece.

But the thing that sticks out for me is the way you get some generations being distinguished. There were really great young players debuting in the late '50s, mid 70s, and now again at the beginning of the teens.

Weird how only one "great" player every year comes out of this good list (thanks Matt), although you could make a case for Drysdale and Mazeroski. 2012 is going to be the exception, I believe.

[31] Thanks, Matt, that's exactly what I was looking for. I assume the names listed in the parentheses are just the standouts and the totals reflect all players? Adding up Trout and Harper's brefWAR I only get 14.3 but Machado is at .6 so that would make it 14.9 and Profar is at 0. Are there any other 19/20 year olds? Looks like this group should be able to get to 3rd place.

Are there any other 19/20 year olds?

Tyler Skaggs is the only pitcher to make the list.

(And, yes, the names are just the guys with 1 WAR or more, except for the years when there were a bunch of 1-2 WAR seasons, then I picked just the most interesting names with 1-2 WAR. Everyone over 2 WAR should be listed by name.).

the funny thing about renteria, and this is totally subjective, but i never thought he looked very athletic. he seemed kind of swaybacked and had a large middle when he played for the cards. it always surprised me that he could (sort of) field his position. quick hands and reflexes make up for a lot i guess.

MLB didn't really get tough with this thing until it came out that Betemit was 14 when he signed.

don't know about that. The Braves (Andruw? or was it Furcal?) and the Dodgers (Beltre) both got in some trouble with the league over this.

As to Renteria off a cliff at 32 ... early demises (in age terms) for early starters are not uncommon at all. Through age 30, Renteria had over 7400 PA. That's nearly as many PA as, say, Jim Edmonds or McGwire had in their careers. A body probably only has so much ML-level baseball in it before the toll becomes too much. Even a lot of the greats.

Leaders in PA <=30:

Ott -- finished at 36
AROD -- far from finished but much diminished as a hitter and hasn't played 150 games since 2007
Yount -- retired at 37
Renteria
Pinson -- retired at 36, only 2.3 WAR ages 32-36
Griffey -- injury-riddled in his 30s, done as a stud hitter after 35.
Foxx -- done at 33
Andruw -- left as an exercise for the reader
Cobb -- aged well
Kaline -- aged well
Aaron -- aged pretty well
Mantle -- injuries galore and retired at 36
Santo -- retired at 34
Mathews -- diminished and essentially done at 35
Ripken -- he was pretty durable
FRob -- made it to 38, might have gone on if not focused on managing

that's all the guys with 7000+ PA through age 30. None of them had short careers obviously, generally making it to 9000+ PA, but a lot of them retired "early". Given that most on that list were still damned good players at age 30, I think (but don't know) that a simple age curve would have projected better overall outcomes for them.

Thanks Walt, I guess its not very unusual.