James Paxton is going to be traded, and he might well be traded very soon. You can never really know for sure what’s going on behind the scenes, now that front offices are increasingly leak-proof, but Paxton rumors have been bubbling to the surface with frequency, and we know Jerry Dipoto isn’t afraid of making a deal in November. The free-agent market is probably going to take its time to develop. The trade market has already opened. Dipoto moved his best catcher. Before too long, he’s going to move his best pitcher.

The Mariners, of course, were just in the playoff hunt for a while. And if there’s something they need, it’s more pitching, not less. More than anything, the Mariners would love to bring an end to their extended playoff drought, and Paxton has developed into something they should be proud of. The Mariners could use James Paxton. The Mariners could use a few James Paxtons. Yet, the big-league roster? It’s not great. And the minor-league system? It’s arguably the worst. Paxton’s looking at two remaining years of club control. The Mariners need to be honest about their timeline. It seems they’ve decided to turn Paxton’s two years into many more years of promising youngsters.

I’m not telling you much of anything you don’t already know. And I already talked about Paxton a little bit the other week. But ahead of any trade, I wanted to write this reminder of just how good Paxton really is. It’s going to be a big-time move, whenever it happens. Give me a few minutes to explain to you why.

Paxton has had something of a step function of a career. He was a hard-throwing prospect, then a hard-throwing big-leaguer, but he never commanded the ball very well, and he was sent to Triple-A after spring of 2016. There, Paxton improved almost in an instant, when Tacoma’s pitching coach had him adjust his arm angle. All of a sudden, Paxton threw even harder. All of a sudden, Paxton worked in the zone. Sometimes pitchers spend years trying to get to the next level. And Paxton, I suppose, took years, himself. But the big change happened in a matter of minutes. Ever since then, Paxton has been a different pitcher.

This next plot contains a lot of information. But I don’t want for any of you to be overwhelmed. Paxton made it back to the majors a few months into 2016. This is just a plot of Paxton’s percentile rankings in the majors since 2016, among starting pitchers. The minimum I used was 200 innings, but Paxton has more than doubled that. Note that xwOBA refers to expected wOBA, and I got that from Baseball Savant.

High marks across the board. Paxton looks the worst if you just look at him in terms of ERA-, but I also care about ERA- the least out of all of those measures, given that Paxton hasn’t always pitched in front of the most capable team defenses. You can get a sense of the scouting and the analytics, here. Paxton’s a big lefty, and he throws hard. Based on the strikes, the walks, and the zone rate, it’s easy to tell that Paxton repeats his delivery and doesn’t often miss by too much. By FIP-, Paxton ranks fifth out of 161 pitchers. By xFIP-, he ranks seventh. By expected wOBA, eighth. From a statistical perspective, Paxton’s built the profile of an ace.

Now, that plot looks back. This plot attempts to look ahead. Here are some of Paxton’s projected percentile rankings, for 2019, according to Steamer. Obviously, I’m limited by what Steamer actually projects, but this tells you most of what you need to know.

Paxton’s projected to be one of the very best starters, by ERA. He’s projected to be one of the very best starters, by FIP. The peripherals are in agreement, which is a given, since FIP is based on the peripherals. No, Steamer isn’t perfect, and no, most projection systems didn’t forecast, say, Gerrit Cole’s 2018 breakout. Trajectories can change at the drop of a hat. But all of Paxton’s indicators are excellent. It’s the indicators other teams will be studying — and have been studying — most closely.

The knock against Paxton is his durability. Whenever Paxton has to miss a start, Twitter fans are quick to the eye-roll emojis, and the fact of the matter is that Paxton’s 160.1 innings this past season were a career high. Paxton hasn’t yet proven himself to be a workhorse. But then, in 2016, between Triple-A and the majors, Paxton made 31 starts, and he was never meaningfully hurt. Paxton did then have a pair of DL stints in 2017, but in 2018, Paxton had a very minor back injury. Then he got drilled in the arm by a come-backer. Then he got sick. Paxton’s shoulder has never exploded. His elbow has never exploded. The problems in 2018 don’t seem like problems with a super high probability of recurrence.

Durability is a tough thing to forecast, anyhow. Not that missed starts and DL stints can be discounted, but Charlie Morton, for example, only just made a career-high number of starts in this past season. Gerrit Cole has exceeded 200 innings two years in a row, but in 2016, he had a pretty significant elbow scare. Paxton will cost less than he would had he never been placed on the DL, but I wouldn’t expect a huge discount. Teams see what Paxton is when he’s healthy, and teams don’t know that much about health. The winning bidder, of course, is likely to be the team expressing the fewest concerns.

If you examine the recent past, and if you examine the 2019 projections, Paxton looks quite a bit like Carlos Carrasco, another high-quality starting pitcher who’s rumored to be on the block. Part of that is because the Indians are worried about their payroll exceeding their budget, but the Indians also presumably understand Carrasco could draw a trade-market overpay, with the free-agent market somewhat thin. And the Indians are also well-positioned to win the AL Central by a healthy margin, regardless. They could step back without stepping back too far. Carrasco could bring them some longer-term reinforcements.

Between Paxton and Carrasco, many of the numbers are very similar. Paxton’s controlled another two years for something like $22 million. Carrasco’s controlled another two years for something like $20 million. Yet Paxton is a lefty, while Carrasco is a righty. Paxton throws the ball a couple ticks harder. Paxton is younger, by more than a year and a half. And unlike Carrasco, Paxton has never had Tommy John surgery. That doesn’t mean Paxton will never require Tommy John surgery, but Carrasco has already blown out once. It’s a risk, that teams are aware of. Paxton’s like Carrasco, but a little bit safer. Paxton really might be this offseason’s best pitcher available.

For that reason, the Mariners have had a big ask. Clearly, it hasn’t yet been met, since no trade has been agreed to, but a trade is coming, and it’s going to improve the Mariners’ future outlook, even though it’s virtually certain to make them worse in the short-term. For as much as we’re living in the era of declining starting-pitcher responsibility, Paxton is one of those guys every team would want in a short series. He’s one of those guys every team would want in a one-game playoff. James Paxton is a potential difference-maker in the rotation, and that’s why the Mariners are asking for young players you’ve heard of. You don’t get a player like this for a song.