Gunnar Henderson Explores the Rolen Zone

Dan Hamilton-USA TODAY Sports

On September 7, 1996, Scott Rolen’s journey to the Hall of Fame took a painful, but perhaps ultimately fortuitous twist. That afternoon, the Phillies played the Cubs at Veterans Stadium. Rolen had recorded his 130th at-bat of the year in the bottom of the first: With the bases loaded and one out, he struck out on four pitches against Steve Trachsel. Two innings later, Rolen came up for what was supposed to be at-bat no. 131. Instead, Trachsel hit him in the forearm with a pitch, breaking the ulna in Rolen’s right forearm.

The 21-year-old Rolen took his base, then tried to gut it out in the field in the top of the fourth. He lasted three batters, then could continue no longer. Jim Fregosi pulled Rolen and replaced him with Kevin Sefcik, one of the dozens of interchangeable Kevins who filled out the rosters of the mid-90s Phillies. Rolen took no further part in the 1996 season.

The following year, Rolen played 156 games, hit .283/.377/.469 with 21 home runs and 16 stolen bases, and cakewalked to a unanimous victory in the NL Rookie of the Year race. It was Rolen’s first piece of individual hardware, and one that would not have been possible had Trachsel not plunked him the previous September.

Astute readers will already know the significance of a rookie’s 131st at-bat. To be rookie-eligible, a player must not have exceeded the following criteria: 130 at-bats, 50 innings pitched, or 45 days on the active major league roster. This constitutes a reasonable concession to the reality that a few games’ worth of major league experience doesn’t mean that much in a player’s development arc. But it can be absolutely maddening to track in practice.

The roster days component most frequently slips through the cracks; it’s easy to forget about altogether. And while the playing time rules haven’t changed since 1971, the way service time counts against the 45-day limit has: Through 2019, the last season of 40-man roster expansion, days accrued after September 1 counted toward a player’s free agency, pension, and so forth, but not his rookie eligibility. Time on the major league injured list also counts toward service time, but not rookie status.

And then there’s the distinction between eligibility for the batting title, which concerns plate appearances, and rookie eligibility, which concerns at-bats. I know nobody cares about your fantasy team but: Just this weekend I drafted Gunnar Henderson in my Diamond Mind league, so I was looking at his 2022 stats with the Orioles. I probably spent a solid minute trying to figure out how he was at the top of so many prospect lists when he’d already accrued 132 plate appearances in the majors. It was only then that I remembered that the important number was Henderson’s 116 major league at-bats.

Ideally, we’d appoint some wise person to make a subjective determination between rookie status and not. Me, for instance. I’d be willing to serve as dictator of the world if the people so desired it. But failing that, objective standards lead to some weird edge cases. Anthony Rizzo, a particularly patient hitter, got all the way to 153 plate appearances his first year without going over 130 at-bats. In 1975, Doug Flynn managed to appear in 90 games as the utility infielder for the Big Red Machine, but only recorded 127 at-bats. (Turns out Pete Rose and Joe Morgan’s backup isn’t going to get that many starts. Who woulda thought?) In 2015, Byron Buxton recorded 138 plate appearances, 129 at-bats, and 113 days of service time. But of those 113 days, 80 (by my count) either came after September 1 or passed with Buxton on the IL (then the DL). So he opened 2016 still on prospect lists and as a heavy favorite for AL Rookie of the Year.

This confusing middle ground — more than 130 plate appearances, but 130 or fewer at-bats — represents a tough needle to thread. (For simplicity’s sake, I’m calling this the Rolen Zone from this point on.) But a couple of position players manage it almost every season. Since 1971, 104 first-year position players have resided in the Rolen Zone. Not all of them have retained their rookie eligibility, however, and the further back in history we go the harder it gets to determine.

Since the strike, as best as I can tell there have been 44 instances of a first-year position player coming to the plate more than 130 times but retaining rookie eligibility the following season. Seven of them received Rookie of the Year votes the following season, including Ryan Mountcastle, who appeared on Rookie of the Year ballots in both 2020 and 2021:

ROY Candidates from the Rolen Zone
Player Season Team G PA AB Next Year ROY Finish
Ryan Mountcastle 2020 BAL 35 140 126 8th (6th in 2020)
Brandon Lowe 2018 TBR 43 148 129 3rd
Josh Bell 2016 PIT 45 152 128 3rd
Yuli Gurriel 2016 HOU 36 137 130 4th
Mike Trout 2011 LAA 40 135 123 1st
Delmon Young 2006 TBD 30 131 126 2nd
Scott Rolen 1996 PHI 37 146 130 1st
SOURCE: Stathead

That’s a small enough number, around two players a season on average, that it’s probably unwise to draw quantitative conclusions. Still, seven Rookie of the Year vote-getters out of 43 players (not counting Henderson) is 16.3%. Compare that to all rookies: In 2022, 234 rookie position players batted at least once. Nine of those received at least one Rookie of the Year vote, a conversion rate of 3.8%.

Of the seven Rookie of the Year vote-getters, six had appeared on someone’s top 100 prospect list at some point in their minor league careers. The one exception, Gurriel, arrived in American pro ball as a 32-year-old who’d spent a decade crushing top competition in Cuba and Japan.

Several other top prospects landed in the Rolen Zone but did not figure in awards voting as rookies, with Rizzo, Buxton, and Dansby Swanson the most notable of those. Several others went on to long and decorated careers. (Brett Gardner, Jake Lamb, Aaron Rowand, to name three.)

Is there something about the Rolen Zone that portends future success? The qualitative elements to a player’s game that might fit the Rolen Zone are patience and power. The larger the gap between a player’s plate appearance total and his at-bat total, the larger the eye of the needle he has to thread to get in the Rolen Zone. Josh Bell had 24 plate appearances as a first-year player that didn’t register as at-bats: 21 walks and three sacrifice flies. Delmon Young had only five.

Well, big league teams call up rookies for one of two reasons: First, they have a hole and need a body, any body, to fill it. Second, they think the rookie either is or will soon become better than the incumbent at the position.

Since 1995, 3,268 position players have appeared in at least one major league game. Of those, 29% didn’t manage to register 131 plate appearances or more in their entire careers. (Or their careers so far.) Two of those players pulled a Moonlight Graham and appeared in one inning of a major league game without batting.

The median figure for plate appearances since 1995 is 557. Among Rolen Zone players who debuted from 1995 to 2021, 35 beat that figure. (Antonio Perez, best known as one of the prospects in the trade that sent Ken Griffey Jr. to the Reds, hit 557 on the dot. He gets to take home the entire jar of jelly beans.) That effect has only gotten more pronounced as teams have become more intentional about things like the 40-man roster and service time. Unless Henderson gets abducted by aliens or receives a call to the priesthood in the next 10 months, all 16 players who got Rolen Zoned from 2013 to 2022 will end up with at least 600 plate appearances in the majors.

Does that mean that the Rolen Zone selects players who are better than Quad-A roster filler? To some extent, that’s probably true. If they perform better, they’ll last longer in the majors. But it’s more important that the player’s team believes he’s good.

Some of these guys, like Henderson, come up and rake from Day 1. Others, like Rolen, have an indifferent prologue to their careers before taking off in their proper rookie season. Still others, Trout being the most prominent example, suck major booty in their first big league go-around and figure it out later. The common thread among these archetypes is that they get lots of playing time, and quickly.

Remember, not every first-year player with more than 130 plate appearances but 130 or fewer at-bats retains rookie eligibility. Some run afoul of the roster days cutoff by hanging around as part-time players; last year, Alex Call spent too long in the majors to retain rookie eligibility.

Usage explains that discrepancy.

Alex Call vs. Gunnar Henderson Usage
Player Service Days G GS PA AB
Alex Call 75 42 29 131 114
Gunnar Henderson 36 34 27 132 116
SOURCE: Stathead

Henderson was the Orioles’ only over-slot pick in the first 10 rounds of the 2019 draft; by the time he was big league-ready, he was considered one of the top prospects in the sport. The Orioles weren’t going to call him up to have him ride the bench. Call was a solid prospect in the draft, and he played almost every day for the Nationals down the stretch. But in between those two things, he was a 27-year-old who’d been in the minors for parts of seven years and had just gone through waivers. There’s less urgency to get him in the lineup every day.

And in order to get near 130 plate appearances in 45 days, you have to play basically every day. Roster filler, backup catchers, fifth outfielders, those guys tend not to get much concentrated playing time. Top prospects do, even if they stink at first.

Henderson’s presence in the Rolen Zone is an auspicious omen; it places him in company with a Hall of Famer on the left side of the infield, even if the criteria for that comparison were invented out of whole cloth in the process of writing this article.

Michael is a writer at FanGraphs. Previously, he was a staff writer at The Ringer and D1Baseball, and his work has appeared at Grantland, Baseball Prospectus, The Atlantic,, and various ill-remembered Phillies blogs. Follow him on Twitter, if you must, @MichaelBaumann.

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1 year ago

Why? Just…why?

1 year ago
Reply to  sadtrombone

Boredom is a powerful thing.

1 year ago
Reply to  sadtrombone

Why write anything?

1 year ago
Reply to  FunFella13

I get that this is the offseason and things are boring but I don’t see any reason for this at all. Someone were to ask you what the Rolen zone was and you tried to explain it you would get blank looks. “What does that have to do with Rolen? Why does this matter?” And your response would have to be “this is a completely insignificant footnote in Rolen’s career and equally insignificant for anyone else’s. It doesn’t matter at all.”

They might ask: Was it at least funny? And you would shake your head sadly.

I don’t LIKE spelling all this out. I prefer “why?” Instead. But you asked.

Smiling Politelymember
1 year ago
Reply to  sadtrombone

Eh, I can accept that some people like articles I don’t (also, Rolen is definitely in the news, so I don’t think it’s quite as insignificant as you claim given the handwringing around his election/skillset).

I’m more upset that “Rolen in the Zone” was right there and, yet, still ignored. Have we abandoned the rhetorical principles that made FG great?

1 year ago
Reply to  sadtrombone

I’m confused. Your objection here is the title? Or that you just don’t find this interesting?

I find it interesting.

1 year ago
Reply to

I object to everything! (it’s safer that way)