Jered Weaver’s Declining Skills
Jered Weaver has made a career out of outperforming his expected ERA metrics. In his first seven seasons, he has posted an ERA below his SIERA in six of those and sports a career 3.27 ERA versus a 3.94 SIERA. Along with Matt Cain, he has become the poster boy for the outlier group whose luck metrics don’t regress to the league average like the majority of Major League pitchers. He’s the exception to the rules.
Of course, we know more now about how batted ball distribution affects some of these luck metrics, like BABIP, and we no longer consider Weaver as fortunate as we used to. Given his penchant for allowing fly balls and inducing pop-ups, it is no surprise that his career BABIP is just .271. Weaver has always displayed solid skills with an above average strikeout rate, primarily due to a nasty change-up, and excellent control. The change-up is extremely effective, despite Weaver possessing underwhelming fastball velocity, especially for a right-hander.
Unfortunately, the solid skills base that Weaver has established is slowly eroding. That means that his ability to suppress hits on balls in play and home runs on fly balls has to be taken up another notch in order for him to remain an elite pitcher. It’s time to look at some charts!
Weaver has never owned a big fastball, as he averaged just about 90 mph when he debuted back in 2006. But check out this trend since 2010.
This chart doesn’t need any explanation. The trend is straight downward. That’s a troubling sign, especially for a pitcher who’s experienced shoulder issues in the past. He’s getting to the danger zone in velocity, if he isn’t already there yet, whereby it makes it extremely difficult to remain a good pitcher, let alone a Major League quality one.
And given that declining fastball velocity, this next chart should come as no surprise.
A lower strikeout percentage isn’t necessarily a terrible thing if it comes along with dramatically improved control. But, it hasn’t.
And the underlying skills behind limiting walks — the rate of first pitch strikes and frequency of pitches thrown in the strike zone – are also headed in the wrong direction.
Weaver’s F-Strike% and Zone% have plummeted this season. Is all this just a matter of a small 34 innings sample size? Perhaps. But there are too many warning signs all rearing their ugly heads at the same time to just brush it off.
There are some glimmers of hope, though. His expected strikeout percentage based on the breakdown of his called strikes, swinging strikes and foul strikes is 19.8%, a bit better than his current mark and higher than last year. Furthermore, his fastball velocity averaged 87.7 mph in his last start, which is nearly identical to his season average in 2012. It was just one start though, so we’ll know more in his next couple of outings when we learn whether his velocity has indeed rebounded.
Whatever the case with the velocity, the significant decline in his ability to throw first pitch strikes and pitches inside the strike zone is worrisome. And last, Jeff Zimmerman’s new PAIN injury finder published in his MASH Report includes Pace as a factor. Zimmerman tells us that injured pitchers take longer between pitches, or in other words, experience an increase in Pace. Well sure enough, Weaver’s current Pace is at a career high.
I would be extremely concerned if I were a Weaver owner and would not be attempting to trade for him if his owner is considering selling. Whether it’s just an age-related skills decline or an injury, this is not the same Weaver we have grown accustomed to.
Mike Podhorzer is the founder of ProjectingX IQ, an advanced fantasy baseball analytics platform that transforms projection data and in-season performance signals into actionable intelligence. He is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year and three-time Tout Wars champion. He is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. Follow Mike on X@MikePodhorzer and contact him via email.





Awesome post with real tractable info! If you are going to do similar ones in the future, quantifying the slope of the trendline would be really nice. I can clearly see they look similar, but I think the case would be crazy persuasive if the BB% is the same or similar slope as the fastball velocity decrease (albeit different signs).
Yeah, I’m having trouble equating BB% and velocity slopes too. I just can’t find the conversion factor anywhere to change walks into MPH so the units are the same. Google is no help. Maybe there’s some walkf/x data I can sift through? Is the speed that people go from home to first base after a BB what I’m looking for maybe?
I was going to trade Cespedes for Weaver in a 12 teamer last night. Now maybe I wont!
Even if Weaver was pitching like normal, still wouldn’t make that trade. It’s personal preference, but I rarely trade a top hitter for a pitcher.
The Angels really have some issues, don’t they?
Hopefully someone less lazy than I can actually look this up but didn’t his brother fall off a cliff like this as well? Jeff was never a star but was at least useful for the Tigs and then turned to mush.
Can’t really compare, as Jeff only posted a sub-4.00 ERA once. Jered has had a much better career.
I was just going to say that like an hour ago but became busy at work. Yes, if someone can do the research I’d be interested in finding out. I know Jeff was good with Detroit and LA up to a point but I don’t think he ever struck out as many batters as Jered
I think wever is not declining, but his pace would go up if he has more men on base. Holding runners on and going through more sign because of guys on second. I think pace could be a causal connection and not causal.
Still I am now looking to trade weaver.
Sorry typo. I think weaver is declining.
Just moved Weaver and Robert Stephenson for Shields in a keeper because of this article. Thank you!
Good trade now, but Stephenson can be special. Would have hoped you’d get a second piece here..
I’m leery of the regressions you’ve plotted, especially the F-strike rate and walk rate.perhaps posting stats by month would be more telling, although you can run into small sample size there too.
They aren’t regressions. They are just the plots of the season rates from 2010-2013.
Shortly before this article I traded Jared Weaver for Adrian Gonzalez, granted his power is down, but in the crazy stat league I’m in, so long as he hits the ball in play like he’s capable of, it sounds as though I’ll come out way on top.