What is Jacoby Ellsbury, exactly?

He's no longer a kid -- he'll be 30 in September -- and has played 581 major league games over six seasons. In five of those seasons he has hit a total of 24 home runs and knocked in 156 runs. In two of his last three seasons Ellsbury has played a total of 92 games, hitting four home runs with 31 RBIs, a batting average of .254 and an OBP of .304. 

For the great majority of his career Jacoby Ellsbury can be safely categorized somewhere between injury-plagued and mild disappointment. Also, though, there's this: He's exactly one great year away from a $150 million contract and enters the 2013 season as the player on the Red Sox roster most capable of carrying the team to the postseason.

Think about it: Isn't Ellsbury's peak the highest peak on this team? In 2011 -- only two years ago, though the juggernaut Sox of July and August of that season feel about a decade old -- he was either the best or second-best player in the American League (Jose Bautista), ranking in the top five in batting average, WAR, slugging, OPS, runs, hits, total bases (led the league), doubles, home runs, extra-base hits and stolen bases. Were it not for the worst collapse in the history of baseball -- which was in no way his fault, Ellsbury put up a .358/.400/.667 in the teeth of a blizzard of on-field ineptitude and off-field dysfunction -- Ellsbury would have been an easy MVP selection. 

Two years ago, a case could be made that Ellsbury, again, still in the middle of his prime, was the best player in the American League. Name me another player on the Red Sox that could be the best player or pitcher in the American League this season. Jon Lester? He's received Cy Young votes one season in his career -- he was fourth in 2010 -- and is coming off his worst year (by far). Clay Buchholz? Close to great in 2010, sure, but has seen his ERA, WHIP and hits per nine innings go up each of the last two years. And he still has never made 30 starts or pitched 200 innings in any season of his career. Right now you'd happily sign for 16-8, 3.40 from both Lester and Buchholz, right? Does anyone put either guy, even at their best, in the class of David Price, Justin Verlander, Felix Hernandez or Jered Weaver? Of course not. 

Everyday players? Well, you've got Dustin Pedroia, who actually has an MVP on his resume. But he has never had a season to match Ellsbury's 2011, and had his worst year in 2012. The reality with Pedroia, still a wonderful player, might be this: He's never going to be more than what he's been over the last five years -- 15-18 homers, .290 average, .360 OBP, .860 OPS, superb defense. No shame in that stuff, obviously, and he's a better bet than Ellsbury to have a productive 2013, but there is clearly an established ceiling. David Ortiz has been the best designated hitter in baseball the last couple of years, but, maybe you heard, is 37 years old and isn't quite ready to run around the bases, which can really get in the way of playing baseball even for a DH. 

That's it, all the serious and semi-serious candidates. Mike Napoli has played more than 115 games in a major league season one more time than Jackie Bradley, Jr., Stephen Drew hasn't slugged over .400 or played more than 100 games since 2010, Shane Victorino is (at best) a mediocre hitter against right-handed pitching, Will Middlebrooks broke his wrist last season, has already had pain in the wrist this spring and -- during a plenty promising rookie year -- posted a truly hideous 70-13 K/BB ratio. Who am I missing? Jarrod Saltalamacchia? David Ross? There's one potential superstar -- Ellsbury's it. A year ago it was different, with Adrian Gonzalez still around and Ortiz coming off of a 146-game season. 

The lineup is weaker than it was a year ago, but the starting pitching is stronger. There is a belief (which I've been absolutely guilty of espousing) that this team is toast if both Lester and Buchholz don't have bounce-back seasons. I don't know -- if, say, Lester is the Lester of 2010 and Buchholz has an ERA around 5.00 is it impossible that the Red Sox stick around in the wild card race with two half-decent seasons from either Ryan Dempster, John Lackey and Felix Doubront and what could be a terrific bullpen? Put it another way: Lester and Buchholz had their worst seasons in 2012 and the team was still in quasi-contention for that second wild card when Ortiz hurt his foot.

Look, there's a better chance of Bobby Valentine managing the Red Sox in 2014 than there is of Jacoby Ellsbury playing center field for the Red Sox.  We know this and we know all the reasons for it. And I have no idea -- zero -- if players are more or less likely to have better seasons in contract years. It seems to be true, but there isn't a definitive study I could find (this should have been a 64 mph fastball down the middle for Bill James in 1986 or 1987, no?) to prove this to be fact or fiction. 

But for the Red Sox to be best-case scenario good in 2013 -- think 90-72, 88-74 -- they need Ellsbury to give historic fodder to those who are convinced that players step up in contract years. This team can potentially survive if Lester or Buchholz have repeat seasons in 2013, but they have no chance if Ellsbury is just another player, the 2010 or 2012 version. He has to be very close to the Ellsbury of 2011 for October to mean anything around here other than four more weeks of another AFC East title march for the Patriots. 

Is he capable? Sure. Is another MVP-type season probable? Nope. Again, here's the history -- one great season, two good seasons and two seasons spent mostly on the DL. The best bet? Let's go with 144 games, .292 average, 14 HR, 70 RBIs and 36 steals. Solid, but nowhere near transformative. 

That'll get Ellsbury to about 100 million bucks, but it won't be enough to get the Red Sox back to the postseason.