It takes a special kind of curmudgeon to dislike James Jones. The dude rocks a Junior Griffey grin, steals bases like a maniac, and carries a batting average that would make your dad raise an approving eyebrow. I can’t remember the last time the Mariners had an outfielder that was this much fun (Sorry, Raul, but your omnipresent look of dread in left field never exactly screamed “fun”). And yet, I find myself dreading each of his plate appearances, sighing deeply whenever I see his name penciled in at the top of the batting order.

Anyone that’s flipped to ROOT Sports this year understands the Mariners need another outfielder. Often, though, the names thrown out as needing replacements are Dustin Ackley or Endy Chavez. Yes, James Jones is a likable guy, but his profile going forward is not of a player worthy of a spot on a playoff contending team. In fact, replacing Jones might be more urgent than Ackley or Chavez.

It’s hard to see Jones as essentially a replacement level player, because he so clearly looks the part of a regular. The athleticism stands out like an exclamation point – you don’t want to give Jones anything but a pass with the eye test, watching him cover ground like he does in the outfield. But UZR, unfortunately, disagrees with your eyes. Let’s take the mandatory moment to pause and acknowledge the size of the sample, but it’s not like Jones got called up last week. His UZR/150 (runs prevented/conceded per 150 games) of -25.6, compiled since his emergence in May, ranks 154th out of 156 qualified field players. You can scream “small sample” and “UZR is flawed” until your face turns blue and teal, but a ranking that drastically low indicates quite clearly that Jones is nowhere near an average center fielder at this point in his career. Yeah, he may not be quite this bad, but the UZR (and DRS, another defensive metric) is one of a well-below average outfielder. You’re probably aware that minus defense can be dealt with, as long as the offense is compensating. Here’s the thing, though: the offense is always going to be below-average. And when Jones’s offensive limitations truly become apparent, it’s going to be near impossible to justify keeping him on a major league roster.

Jones just doesn’t have the peripherals to even approach the level of a league-average hitter. Let’s take his current statistics at face-value — a 19.7% strikeout rate and a .056 ISO — and assume they’re sustainable across an entire season (which is an optimistic assumption). On the nifty FanGraphs filters, I isolated single seasons from 1999 to 2013 where hitters put up K% rates at or above and ISOs at or below Jones’s current level, since the goal here is to see whether he could fill the role of an outfield regular. No regular player in that time span has kept up a strikeout rate that high and ISO that low for an entire season. The closest comparison to Jones would be Gregor Blanco’s 2008, where he put up an 89 wRC+, propped up by a 14.3% walk rate. So, basically, in order for Jones to find even slightly below-average success at the plate with his current plate discipline, he needs to both buck recent historic trends AND bump his walk rate up 10 percentage points. The disheartening thing here, though, is that an 18.5% strikeout rate might be overestimating Jones’s potential.

Both Jones’s recent performance and his future projections just don’t see Jones sustaining his current K%. In July, he’s striking out at a 26.9% rate, with no subsequent increase in ISO. ZIPS, a trusted projection system, foresees Jones carrying a 26.4% strikeout rate the rest of the way. Any way you slice it, Jones combines too high of a strikeout rate with too little power to be an effective major league hitter, at least in his current state. Only one player from the last 15 years has qualified for the batting title carrying a 20% strikeout rate and a .075 ISO, and his wRC+ was 58.

That was a whole lot of negativity about James Jones, so let’s back up a little bit. None of this is to say Jones is doomed to the land of washouts. While, at age 25, he’s a bit older than your typical prospect, there’s certainly still time for Jones to improve. He clearly has the physical tools to be a plus center fielder, which is a valuable asset on its own. He’s run above-average BABIPs his entire career, demonstrating an ability to leg out plenty of infield hits. And if he could add just a little bit of power — say, get his ISO up to .100 or so — the prospect of playing Jones would look a lot more tenable.

But the Mariners are in the heat of a pretty tight playoff race, and every little contribution matters. Right now, James Jones might be one of the worst major league regulars, and now is not the time to be experimenting to see whether he’s worthy of future playing time. It’s a shame to say, because yes, he runs fast and gets lots of hits and makes dope catches. But at this point in the season, James Jones is just not good enough to be an everyday outfielder.