There’s an interesting comparison to be made between Jacoby Ellsbury and Michael Bourn, which is why I’m beginning this post with a couple paragraphs about Bourn before moving on to the meat. Bourn, you’ll remember, was a free agent just last offseason, and while he didn’t bring star power to the table, it would’ve looked like he did just by WAR alone. The big draw was supposed to be Bourn’s legs. Agent Scott Boras called him “by far the best defensive center fielder in the game.” He could run on the grass, he could run on the dirt, and he was a leadoff hitter who hardly embarrassed himself with the stick. Bourn was to be a fine hitter who really excelled in other areas.

There’s one thing, though, that did and still does get me fascinated. Bourn’s a little guy, and he doesn’t hit for pop. His spray charts convey as much, occasional dinger be damned. You don’t sign Michael Bourn in order for him to drive multiple runners to the plate at a time. But I played around on the ESPN Home Run Tracker, and according to the site, in April 2009, Bourn hit a home run 457 feet. Or, 456 feet, under standard conditions. He’s never come close to reaching that distance otherwise, which is a big reason why that discovery came as such a shock, but the way I took it was that that established a ceiling. Somewhere in there is a hitter capable of hitting a baseball 450 feet, because Bourn had done it before in a game, once. Maybe that’s a stretch, but then it’s a tough homer to fake.

Bourn approached free agency in his age-28 and age-29 seasons. Ellsbury, too, has approached free agency in his age-28 and age-29 seasons. Compare those sets of seasons and the players look remarkably alike.

Player Age PA ISO wRC+ BsR Def WAR WAR/600 Michael Bourn 28-29 1425 0.104 104 19.8 21.6 9.9 4.2 Jacoby Ellsbury 28-29 959 0.118 103 16.7 16.0 7.2 4.5

Identical offensive production, identical baserunning, identical defense. Yielding basically identical value, once you adjust for playing time, which matters since Ellsbury was hurt. Neither player hit for much power over the window. Neither player walked a ton, and both players had higher than average hit rates on balls in play. Both players were extended qualifying offers. Both players have been represented by Boras. Bourn ultimately signed for $48 million and four years. Ellsbury is said to be looking at or for nine figures.

There are certain differences that tip the scales in Ellsbury’s favor. For one, he’s just long had the better reputation, having been a first-round draft pick. Ellsbury has a more classic baseball body than Bourn, and he’s proven that he can get the job done under the Boston spotlight. More tangibly, Ellsbury doesn’t strike out as often as Bourn does, the better contact suggesting a better bat tool. Bourn is seen as a slap hitter; Ellsbury’s just seen as a hitter.

But there’s another thing, maybe the biggest of all things. If I say the words “Mike Trout Season,” you have an idea what I mean. This is how I’m choosing to classify an incredible all-around season, and I’m somewhat arbitrarily setting my cutoff at nine WAR. Basically, a Mike Trout Season is any season in which a position player was worth at least nine wins above replacement. Appropriately, the most recent Mike Trout Season was posted by Mike Trout, in 2013. Before that, we’ve got Mike Trout, in 2012. Before that, we’ve got Jacoby Ellsbury, in 2011. Then you have to go back to Alex Rodriguez in 2007. Then it’s back to Barry Bonds, Scott Rolen, and Adrian Beltre in 2004. Over the course of the last decade, there have been seven Mike Trout Seasons, two from Mike Trout, and one from Jacoby Ellsbury. You’ll notice there have been none from Michael Bourn.

As recently as 2011, Ellsbury was probably the most valuable player in baseball. He was the Mike Trout of that year, and that year was not far back, and Ellsbury is not old. Mike Trout’s performance level is almost inconceivable. Ellsbury just about achieved it. And a big part of that season were his 32 home runs. Over the rest of his regular-season career, he has hit 33 home runs.

What Ellsbury did in 2011 was like a season-long equivalent of Michael Bourn’s one really long homer. It established, for Ellsbury, a performance ceiling, as good as almost anyone else’s on the planet. The way I figure, it’s hard to fake a dinger that goes 450 feet. It’s way harder still to fake being a nine-win player over 158 games and 732 trips to the plate. Ellsbury was everything — he was durable, he hit for average, he hit for power, he ran well, he defended well, he hit at the top of the lineup. There was nothing else for him to do, and there’s no way that version of Ellsbury is completely and utterly dead. At least, that’s what Scott Boras is going to be pushing as an idea too compelling, too juicy to ignore.

It writes itself. Ellsbury was a superstar in 2011. Early in 2012, he injured his shoulder in a freak accident at second base. Those injuries take a while to heal, and Ellsbury might still be getting stronger, a year and a half after the fact. Even below 100%, he helped this year’s Red Sox win a title. Ellsbury hit only nine home runs, but when he woke up on Independence Day, he had one. Over his remaining 55 games, he hit eight, suggesting there could be even more on the way. Suggesting Ellsbury could still get back to something like what he was, when he was amazing.

Ellsbury has hit 32 dingers in a year. He’s hit multiple dingers more than 425 feet, and he’s topped out at an impressive 446. He’s not a slap hitter the way that Bourn is, and it’s easy to see power in his frame, and given his swing. The two years headed into free agency, Ellsbury and Bourn hit for similar amounts of power. But they’re thought of very differently in that regard, and Ellsbury’s ceiling is going to drive up his price presumably to and beyond $100 million. It doesn’t matter if Ellsbury is unlikely to be amazing ever again. What matters is the existence of the possibility, because it just doesn’t work to call Ellsbury’s 2011 a fluke and write it off entirely. It happened, and it was done by this player, on the market. This player has been Mike Trout, and then an accident happened.

The crowd, a year ago, projected Bourn for five years and $70 million. This year, the crowd has Ellsbury at six years and $112 million. Bourn wound up settling for a relative discount, but the Ellsbury numbers seem about right. He has the talent, he has the reputation, and thanks to 2011, he has the established performance ceiling that would rank him with anyone else in the game. Nobody’s going to think that they’re signing Mike Trout. Plenty are going to think that they might be, and those executives won’t be wrong. There’s just no ignoring what a player has done, and there’s definitely no ignoring what Ellsbury did.