Living things age Jason Motte Jersey , and baseball players are no exception. Unfortunately, the details of aging in a baseball context have not been steady over time. A homer has always been a homer, but a..."WhiteFanposts Fanshots Sections Talking Chop Users GuideTalking Chop PodcastAround the NL EastBaseball Analysis PrimerTalking Chop Baseball Analysis Primer: AgingESTShareTweetShareShareTalking Chop Baseball Analysis Primer: AgingRobert Hanashiro-USA TODAY SportsLiving things age, and baseball players are no exception. Unfortunately, the details of aging in a baseball context have not been steady over time. A homer has always been a homer, but a 27-year-olds potential has differed over baseballs long history. That tends to lead to some confusion and consternation. There was a point, where baseball was perhaps a little less deeply analyzed, that players got called up, and sort of floundered around while they gained experience. If good players got called up their early 20s, the general idea was that theyd figure out how to succeed in the majors by their late 20s, before aging made them unable to keep up with their younger peers, until they had lost so many steps, bat speed, or ticks on their fastball to be worth rostering at all. Under this premise (which was not just a premise, but an observed phenomenon since World War II through the late 2000s), players were fairly weak performers if called up around 21-22, continued improving through age 26 or so, then had peak performance (all of this is on average, every player is different!) from 26 through 28, and then declined fairly steadily. The result of this was an upside down U-shaped curve, where, relative to his peak, a player would be just as bad at age 21 as he was at age 35.TC Baseball Analysis PrimerWAR Hitting FieldingBase Running Pitching AgingSurplus Value MathSince then, though, things have changed, and some of the best evidence originates from this Jeff Zimmerman piece at Fangraphs: … -decline/. That article features the following chart:You can see that all lines but the green line look pretty similar, and have that upside-down U shape. But, the green line reflects data for the most recent group of hitters, and is instead like a warped hockey stick: its flat, and then features the same age-related decline curve. But, as the hyperlink to it says, the big finding is that hitters no longer peak, only decline. That doesnt mean they start declining right away; the decline doesnt get notable until around age 29. And again, this isnt some kind of hard-and-fast rule for every hitter, it just describes what happens on average across the whole population. But, its a substantial deviation from the way things used to be.So, when someone tells you , We should get this hitter, hes 26 and is going to be in his prime for the remainder of his team control years, just remember -- that may have been valid in the past, but its not the past any longer. Pitcher aging curves have also been researched and summarized by Zimmerman (and Bill Petti), here: … roduction/ and here: … elievers/. These articles (like everything linked in this primer) are well worth reading in full, but the striking thing is that the pitcher aging curves here are much more in line with the new hitter aging curves than the old ones. The general idea, again, is that pitchers tend to be relatively consistent from call-up to around 29 or 30, and then start to decline. Unlike hitters, there are some competing effects: pitcher walk rates actually do improve as pitchers get more experience, but velocity starts falling off almost immediately. The tension between these two things prevents there from being an overall effect on run prevention, but eventually the velocity decrease becomes too great to overcome, and walk rates go up as well, accelerating the decline.Its also worth noting that reliever aging curves are just a mess. I dont mean intuitive, I mean depressing. According to the Zimmerman and Petti work, relievers actually maintain velocity after call-up a little better than starters, but their walk rate starts getting worse almost immediately. As a result, relievers age terribly. According to one of the charts in the links above, a 23-year-old reliever sees, on average, an FIP increase of 1.00 by age 26 or so. By age 30, that increase is an average of 1.50. Considering that average FIPs have been in the 4.00s, this means that an average reliever thats age 23 will be hilariously unplayable at 30. A reliever will need to have an FIP in the low 3.00s to be average by the time hes 26, or in the mid-2.00s to be average by the time hes 30. Some relievers will hang on, sure. But theres no great reason to count on any given reliever learning how to pitch or anything like that.Before the 2018 season, I tried to come at this topic a different way, focusing instead on experience rather than actual age. I found pretty much the same thing: players have much greater odds of getting worse rather than getting better with every subsequent year. You can find that work here: … xperience. Whats the use of knowing all this? Well, aside from general knowledge, these aging curves help to explain how aging factors into forecasting player performance. One common rule of thumb used these days is that a player will stay the same up until or through age 30, then decline by 0.5 WAR per full season until or through age 35, and then decline by 0.75 WAR per full season thereafter. Thats actually pretty sizable: a perfectly good 3 WAR player will become just average in his early 30s, a bench guy before his mid-30s, and should be not-quite-deserving of a roster spot a few years after that. Again, not all projection systems will use similar assumptions, and this is a very rough, average way of thinking about aging in player forecasting. But, we know aging happens Brett Cecil Jersey , so ignoring it seems unwise. When looking multiple years into the future, which happens most often when evaluating trades or considering potential free agent contracts, aging matters quite a;dr takeaway for aging - player primes are no longer late 20s. Players tend to decline at/after 30 years of age, and decline is pretty constant until theyre out of baseball. Pitchers also decline, and before they hit 30, their command tends to improve while velocity is always declining, which cancel each other out. In general, dont assume that players will get better once theyve debuted, because most dont. Despite a surge of write-in votes for Daniel Descalso (I know who THOSE were from...), Corbin went out of Arizona on a high."There were at least two points in Patrick Corbins career where him winning this award for the second time seemed very unlikely. The first was at the beginning of the 2014 season. Our reigning Pitcher of the Year was robbed of a chance to be our Opening Day starter in the Sydney series, by an elbow injury that required Tommy John surgery. Coming back from that is always a roll of the dice, but Corbin recovered and took the mound for the second half of the 2015 season. But his campaign the following year was terrible, and in mid-August, with an almost Shelby Miller-like ERA of 5.58, Corbin was moved to the bullpen. Weve seen pitchers go that way and never come back e.g. Archie Bradley and Daniel Hudson, so there was legitimate concern wed seen the last of Patrick as a starter. However, Corbin was returned to the rotation in 2017 and provided a solid season, posting a 4.03 ERA, and not missing a start. That set the table for his final year before free-agency, and a thoroughly motivated pitcher came out of the gates firing. With Zack Greinkes groin tightness keeping him out for a few days, Patrick finally achieved the Opening Day start for Arizona he had been denied four years previously, and got the W in an 8-2 victory over Colorado, throwing 5.2 innings of two-run ball. Much better was to come, however, as he went undefeated in his first eight starts. He blanked the Dodgers for 7.1 innings of one-hit ball on April 4, then one-hit San Francisco 13 days later, our Performance of the Year.That was just the best of many very good performances from Corbin. He had two games where he struck out a dozen opposing batters, walking one and zero hitters. That made him the first Arizona pitcher with multiple games like that (12+ Ks, 0/1 BB) in a season since Randy Johnson in 2004. His 12 strikeout, no walk outing on June 22 in Pittsburgh was also only the second such since then (Robbie Ray had the other, in 2017). When Patrick had his slider working, he was almost unstoppable: across the nine games where he had 9+ strikeouts, he allowed only 37 hits in 59 innings, with a staggering K:BB ratio of 90:7, with a WHIP of 0.75.It was an especially remarkable performance, considering there were concerns about his diminished velocity in May, leading to articles with headlines like The Diamondbacks Could Have a Patrick Corbin Problem. His four-seam fastball averaged 92.8 mph in 2017 , but against the Dodgers on May 3, was only 89.7 mph. While both pitcher and team professed no great degree of worry about the suddenly missing mph, the Diamondbacks were bothered enough to have Corbin skip bullpen sessions between starts. The velocity did eventually return, but took its time about it, Patrick not averaging 92 mph again until September. However, youd be hard pushed to say that he missed it. A key factor this year was his ability to get out right-handed batters. Look at the difference in his split against them, comparing last season to this:2017 vs. RHB: .292/.348/.482 = .830 OPS, K:BB = 2.412018 vs. RHB: .213/.259/.324 = .583 OPS, K:BB = 5.67Right handed-batters hit almost two hundred and fifty points worse against Corbin last year, and struck out in 30% of the plate-appearances. Youll know why, if you watched one of his starts. You would have seen him deliver a Big Unit-esque slider, diving in to the ankles of right-handed batters.It wasnt nearly as hard as Randy Johnsons 98-mph Mr. Snappy, averaging only 91.3 mph. But it was particularly effective when combined with a slower version - classified by Pitch f/X as a curve, coming in at 72.8 mph. He used this a lot in fastball counts, either to get back into the count or get ahead. And he did so regularly, getting strike one a career-high 64.2% of the time, which put him the drivers seat. After that first strike, batters were held to the tune of .191/.239/.287. Few pitchers generated less contact than Corbin: at 25.7%, his swinging strike rate was the highest of any qualifying pitcher in the majors, and the overall contact rate of 65.3% trailed only Chris Sale (65.0%). The resulting strikeout rate of 11.1 per nine innings was more than 30% up on the 2017 figure, which was already a career high for Patrick to that point. He became one of only fourteen qualifying pitchers in baseball history with a season where their K-rate was better than 11 and their K:BB ratio was above 5. [Though in a startling testament to the rise of the K in recent times, nine of those have come over just the last four years, with Randy Johnson, Curt Schilling and Pedro Martinez the only men to have done it prior to 2014] His All-Star selection in July - the second for Corbin, following on from 2013 - was testament to that, as was his fifth-place finish in Cy Young voting. He was a free-agent this winter, and got what is to this point, far and away, the biggest contract of the off-season. Corbin signed a six-year deal with the Washington Nationals, worth $140 million - thats more than twice the next-highest in total value, the four-year, $68 million deal inked by Nathan Eovaldi with Boston. His departure undeniably leaves a big hole in the Diamondbacks rotation for 2019 that will be hard to fill. He leaves Arizona fourth on the all-time franchise list for wins (56), third for strikeouts (897), and seventh for pitching WAR (11.4). His 246 Ks last season were the most by any non-Johnson/Schilling player, and the highest figure for Arizona since 2004. The Pittie for Best Pitcher was well deserved.