The same way you can cut down a tree and count the rings to determine its age, you can find out how old a baseball fan is by asking him who his baseball peers are. All baseball fans go through the stages of aging by Baseball Woodersonism. We keep getting older, but all those baseball players stay the same age.

Thus, the stages of Baseball Woodersonism:

Youth. All baseball players are older than you. They all seem eternal and massive, like redwoods.
Peerism. Rookies are your age; you watch up-and-coming prospects while doing collegiate keg stands. The world spreads out before you, limitless.
Peak years. This is when you are the same age as the superstars, mid-to-late 20s, when players are at their absolute best and you start worrying, "Hey, I should have a lot better idea of where my life is going than I do."
Established veteran. This is when the players who were rookies when you were in college started getting called "grizzled."
Retirement. It is incredibly disturbing when baseball players your age start retiring and you're still figuring out how to tackle that student loan.
Manager. "Wait, how in the world is Dave Roberts -- that Dave Roberts? -- old enough to be a baseball manager?"
Death. Fortunately, we are all immortal and will never die.

I'm still young enough to have current Major League players older than me … but just barely, and I've only got a couple of years left. My example of this is always Placido Polanco, who was born on the same day as me, Oct. 10, 1975. He was a promising rookie, an established regular, a reliable vet and then … he was out of the game, just like that. A year ago, Polanco said he was "90 percent retired." There has been no formal announcement, but I assume he is all the way now.

There aren't many guys left. And they're coming for you next. Here are the 10 oldest players in Major League Baseball. Where do you stand on the list?

10. Jason Grilli, Atlanta Braves
Birthdate: Nov. 11, 1976 (39)
Contract situation: Signed through 2016, with $3 million team option for 2017
First season: 2000

Career WAR (via FanGraphs): 6.5

You have to respect a guy who ruptures his Achilles at age 38 and not only comes back for the next season, but actually looks like he's going to be a closer. Grilli might not have a ton of opportunities to close games with the Braves, but the job is his and he's feeling healthy again. He also seems to appreciate every day as a player as much as we all would, as chronicled on his Twitter account, @grillcheese49.

9. Matt Thornton, San Diego Padres
Birthdate: Sept. 15, 1976 (39)
Contract situation: Signed to Minor League contract
First season: 2004
Career WAR: 11

The Padres just signed him a couple of weeks ago, and he's actually old enough that he went through his own (far more minor) version of the Drake LaRoche story years ago.

8. Joel Peralta, Seattle Mariners
Birthdate: March 23, 1976 (40 on Wednesday)
Contract situation: Signed to Minor League contract
First season: 2005

Career WAR: 4.2

The Mariners are calling him the "surprise of camp," and hey, by age 40, that you're doing anything in baseball is a surprise. A neck injury derailed him in Los Angeles last year, but Peralta has been excellent in Mariners camp and might just sneak onto the roster.

7. David Ortiz, Boston Red Sox
Birthdate: Nov. 18, 1975 (40)
Contract situation: Signed through 2016, retiring at end of season
First season: 1997
Career WAR: 46.1

So, this is the year Big Papi says goodbye. It's difficult not to miss him already, though it feels strange that he's still angry about the Twins' disastrous decision to release him after the 2002 season. I think it turned out well for you, Papi. It's amazing how well he's still hitting; his 37 homers in 2015 were his most since 2006. It sure would be nice to see him in one more postseason.

This is where I have to step in and note that every player left on this list is older than me. Still hanging in!

6. Randy Choate, Toronto Blue Jays
Birthdate: Sept. 5, 1975 (40)
Contract situation: Signed to Minor League contract

First season: 2000
Career WAR: 3.4

Is there any reason Choate can't just face a left-handed batter every couple of days until he's 70? Well, last year was a bad sign: Lefties got on base at a .333 clip against him, which isn't great but way too high for a pitcher who claims the ability to get them out as his lone trick. Aaron Loup's injury in Toronto opened the door for Choate to try to sneak one more season and maybe reestablish himself. I wouldn't want to walk away either.

5. Alex Rodriguez, New York Yankees
Birthdate: July 27, 1975 (40)
Contract situation: Signed through 2017
First season: 1994
Career WAR: 114.1

It is a sort of perfect symmetry to A-Rod's career that by the end of the contract that for so long looked terrible for the Yankees, the team may end up needing him after all. Rodriguez was a godsend in 2015, not only hitting his most homers since 2008 but also somehow making 620 plate appearances. The Yanks are counting on him just as much next year, and heck, at this point, maybe he'll even sign somewhere else after his contract at last runs out after 2017. Just 27 homers until Ruth, kids.

4. Koji Uehara, Boston Red Sox
Birthdate: April 3, 1975 (40)
Contract situation: Signed through 2016
First season: 2009
Career WAR: 10.9

He's not the closer anymore, and he's experimenting with a new pitch for reasons no one quite understands, but that splitter -- when it's working -- is still unhittable. If Uehara is healthy, he'll combine with Craig Kimbrel for a devastating 1-2 punch in that bullpen. But "if he's healthy" is a phrase that tends to pop up a lot in listings like this one.

3. R.A. Dickey, Toronto Blue Jays
Birthdate: Oct. 29, 1974 (41)
Contract situation: Signed through 2016
First season: 2001
Career WAR: 16.1

Remember: Cy Young Award winner! Dickey keeps chugging along, and he even settled down a bit last season, enough that the Blue Jays picked up his option in the offseason. Toronto has the best offense in baseball and simply needs Dickey to give it 200 innings of league-average pitching. The free-thinking, fascinating knuckleballer that is R.A. Dickey will never be "average" anything, but if he has another "average" year in 2016, you can count on him being back in '17.

2. Ichiro Suzuki, Miami Marlins
Birthdate: Oct. 22, 1973 (42)
Contact situation: Signed through 2016, with a $2 million team option for 2017
First season: 2001

Career WAR: 56.7

Just 65 hits to go to finally … make … it … to … 3,000. For all the ugliness of Ichiro's past few seasons -- he has been a league-average hitter only once since 2010 -- we will all celebrate when he finally reaches 3,000, which you would hope would be this season. His 438 plate appearances last year were far, far too many … but you worry he may need nearly that many to reach 65. Let's hope Ichiro makes it. We're all cheering for him, for every reason you can think of.

1. Bartolo Colon, New York Mets
Birthdate: May 24, 1973 (42)
Contract situation: Signed through 2016
First season: 1997
Career WAR: 47.9

Ah, Bartolo, Bartolo, Bartolo. He's still, somehow, hanging in as there as a pitcher, though is performance this spring is, well, let's say concerning. Just hang on for the GIFs, man. Hang on for the GIFs.

BartoloBelly 

Players who were among the 20 oldest players in baseball in 2015 but are not currently on a Major League roster: Scott Atchison (retired and now a scout for the Indians), Rafael Betancourt (retired), Joe Beimel (still looking for a job), A.J. Burnett (retired), Bruce Chen (retired), LaTroy Hawkins (retired), Tim Hudson (retired), Torii Hunter (retired), Joe Nathan (still looking for a job) and Randy Wolf (retired).

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Email me at leitch@sportsonearth.com; follow me @williamfleitch; or just shout out your window real loud, I'll hear you. Point is, let's talk.

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