“Old” isn’t disconcerting.

We know what we’re seeing when Chase Utley and Ichiro are more salt than pepper up top, or when R.A. Dickey sneaks slop past hitters who weren’t born when he was drafted. To watch a former star at the end of his career is to look back on a professional life that was well lived and will continue until the player decides it’s time.

What’s disconcerting is Andrew McCutchen playing right field.

From the moment McCutchen first set foot on a big league field in 2009, he was a lock for a high OBP, with about 20 home runs and 20 steals every year. McCutchen went on to post three straight .300/.400/.500 seasons with three straight top-three MVP finishes, and he did it all with style and a huge grin on his face. Mike Trout is the crew cab version of what McCutchen was from 2012 to 2014.

That ended in 2016. Baseball-Reference, whose defensive metrics have never been kind to McCutchen, rated him as below replacement level, and by any standard it was the worst year of his career. Now McCutchen, who’s never appeared in a regular-season game anywhere other than center field and turned 30 in October, is ceding the position to Starling Marte.

It’d be one thing if McCutchen were Joe Mauer, forced by injuries to move from the position that made him an MVP to one that doesn’t suit him as well. Or if McCutchen were Albert Pujols, a future Hall of Famer handing the torch to his team’s next superstar as he follows a familiar aging curve. But McCutchen’s case is tougher, because there’s so much uncertainty around it — was his down year an injury-induced anomaly or the new normal?

The truth is somewhere in the middle: McCutchen was certainly hampered by his bum wrist last year, but even with a full recovery, will probably never be the player he once was.

Athletes slow down when they hit age 30. The speed and impact of that decline varies from player to player, but McCutchen won’t run as fast or jump as high in 2017 as he did in 2010. Sometimes that decline happens on a smooth slope, while other times it happens all at once. McCutchen’s wrist injury made it tough to tell whether his struggles were the result of age or pain — or both, and in what proportion.

The projections systems seem to favor a gentle decline — at Baseball Prospectus, PECOTA’s median outcome for McCutchen in 2017 is a .292/.382/.494 batting line, good for 4.2 WARP. At FanGraphs, ZiPS largely agrees, penciling McCutchen in for a 4.0 fWAR season and a .278/.371/.477 slash line. One quirk of projections systems is that the wealth of data they draw from makes them slow to react to acute changes in a player’s ability. This is both a strength and a weakness: PECOTA won’t pick up on a mechanical tweak that unlocks power in a player’s swing, but neither would it overreact to a slump or short-term injury.

In the first week of August last year, Pirates manager Clint Hurdle finally benched his struggling star, as nothing else had seemed to work. Whether having a few days off allowed McCutchen to heal or just to refocus, after he came back he hit .284/.381/.471 over his last 56 games — almost exactly what PECOTA and ZiPS think he’ll hit in 2017.

Historical precedent is also against McCutchen being cooked. Among McCutchen’s 10 most similar players through age 29 on Baseball-Reference, seven remained productive through their 30s. Reggie Smith had his two best offensive seasons for the Dodgers at ages 32 and 33; Andre Dawson made five straight All-Star teams from 32 to 36, including his MVP campaign in 1987; other names of note include Billy Williams, Dave Winfield, Carlos Beltran, and Gary Sheffield, all of whom are either in the Hall of Fame or should be. Even Matt Kemp’s decline is probably overrated a little — he hit 35 home runs last year and would be a valuable player as a DH, though since Kemp plays in the National League he bleeds as much as two wins of value as a left fielder.

Related Rob Manfred Is Better at His Job Than Anyone in Baseball

The Pirates can’t exactly wait and see whether McCutchen will turn into either Beltran or Vernon Wells. They have to make a $13.5 million decision on McCutchen for 2018, and even that probably undersells the importance of his 2017. It’s not just about the team option, it’s about the contract McCutchen would command for age 32 and beyond, and it’s about Pittsburgh finding a home for outfielder Austin Meadows, FanGraphs’ no. 5 global prospect. It’s about what McCutchen could bring back in a trade if the Pirates decided to cut bait. And it’s also about whether the Pirates want to reckon publicly with cutting loose their biggest star since Barry Bonds.

That’s part of the reason the Pirates and Nationals — despite a much-publicized flirtation between the two clubs — couldn’t hammer out a deal for McCutchen this past offseason. Expectations matter for teams too.

The Pirates as a whole face a level of uncertainty that makes this process even more difficult. After making three straight wild-card games (and losing the last two), Pittsburgh went 78–83 in 2016. In the past 16 months they’ve traded away Neil Walker, Mark Melancon, and Francisco Liriano, and their best hitter in 2016, Jung Ho Kang, is having trouble getting a visa after an offseason DUI in Korea, his third since 2009. (Kang was also accused of sexually assaulting a woman in Chicago in June.)

Related Félix Hernández and the Art of Rebuilding a Former Ace

Meanwhile, no matter what they do, the Pirates are unlikely to catch the Cubs in the NL Central; PECOTA projects the Pirates to finish 81–81, in second place and 12 games behind Chicago. And their status as a small-market team, while frequently exaggerated, limits their ability to spend. As if that weren’t complicated enough, the Pirates have two well-rounded young outfielders who could replace McCutchen — Marte and Gregory Polanco — and in Meadows will soon add a third.

In other words, it’s a complicated situation, and would remain so even if Pirates GM Neal Huntington knew exactly how good McCutchen would be in 2017.

Growing old is scarier than being old. When you’re old, at least you know where you stand.