To What Will Casey Janssen Rebound in 2015?

As we head into 2015, it's clear that while the Jays have made some substantial upgrades, there remaining some glaring weaknesses. Such as the bullpen, particularly right-handed options. At this point, there aren't a ton of palatable options on the free agent market; however, there is one name of particular interest in one Robert Casey Janssen.

From 2011-13, Janssen was the rock at the back of the Jays pen, emerging as a bona fida closer at age 29. Entering his walk year in 2014, he appeared to be in line to cash in, especially after an excellent first half. As we know, things took a bad turn after food poisoning over the All-Star break, resulting in a very poor second half in which he lost the exclusive closing job, and expressed some frustrations with management. Or so the narrative goes, which isn't so true as we will see below. Janssen's also dealt with a variety of injury issues over the past couple years.

Given the Jays needs and Janssen's track record and tenure, bringing him back seems like a natural fit especially since he hasn't been scooped up yet in a hot market for relievers. Of course, for all we know Janssen may not want to come back, or the Jays may not be willing to meet his price or what another eventually offers. But the biggest single factor in all of this is what exactly can be expected of Janssen going forward, in 2015 but also beyond. Can he bounce back to what he was?

Let's start with looking at Janssen's numbers and components from 2011-2013:

Two things stick out: Janssen was an elite pitcher, and a remarkably consistent pitcher. He prevented earned runs 40% better than league average (59 ERA-), 33% better by FIP and 25% above average by xFIP, all excellent marks. The year-by-year numbers showed a machine-like lack of variation around the averages, which is ideal.

Drilling at the components, it's pretty obvious why Janssen was so good: he struck out significantly more batters than average, limited walks, and managed contact well both in terms of preventing hits and preventing home runs. Despite lacking the knockout stuff usually associated with elite relievers, he did everything well and nothing poorly.

Now let's turn to 2014, broken out in pre- and post-All Star break/food poisoning:

In the first half, Janssen was better than ever at preventing earned runs and limiting damage on the three true outcomes. However, the overall numbers masked a major red flag: Janssen's strikeout rate fell by almost one-third compared to 2011-2013, from 25% to a below average 16.7%. Granted, it's a small sample, but even in 22 innings strikeout rate has a reasonable signal-to-noise level. Janssen compensated by walking just one batter and not allowing any home runs. Results-wise, that's great, but no pitcher regardless of how great their command is going to just walk 1% of batters or allow no home runs over a sustained period of time.

In the second half, the bottom fell out. Janssen's strikeout rate fell further to 13%, and his walk rate regressed from otherworldly to a merely great 4.6% (more in line with the 5.7% in 2011-13). He got stung by the long ball, and his BABIP jumped, though was still good. Interestingly, despite the very messy results, his velocity was better in the second half, closer to 2013 than the first half of 2014 when it was down almost a full tick.

The second half numbers are badly skewed by an ugly stretch at the end of July into mid-August that directly followed the food poisoning. If we look at the last 6 weeks of the season (admittedly a somewhat cherry picked start point), things look much better and more normal. Janssen's ERA is still ugly, but his strikeout rate at 17% is back to the first half level, his walk rate is very good, his BABIP is reasonable, and he limited long balls. At 89.8 MPH, his FB was almost back in line with 2013 when he was excellent.

Unfortunately, we're still left with the unescapable reality that Janssen's strikeout rate collapsed in 2014, both in the first half when he looked really good, as well as the second half when he didn't. If this is just a one year blip, then Janssen is an excellent bounceback candidate, and could still serve as a closer or high leverage reliever. On the other hand, if it's the new normal, then Janssen is probably at best a decent middle reliever from here on out.

So the critical question is, what are the odds he bounces back? To get an idea, I built a comparison set of relievers similar to Janssen who also suffered a collapse in strikeout rate. I started with all pitchers from 2000-14 who threw 100 relief innings over 3 seasons with a strikeout rate of at least 20%, and then in the 4th year saw their K-rate fall by at least 5% in a minimum of 15 innings. I further limited to the set to pitchers who pitched in the 5th season (this weeds out Tommy John pitchers and those with other catastrophic injuries Janssen didn't have), as well as those within two years of Janssen's age at the beginning of the sequence. This leaves 54 pitchers, with the results summarized below:

On average, this group of pitchers pitched about 185 innings with a 26% strikeout rate, very similar to Janssen's 25% over 172 innings from 2011-2013. In the 4th year, their strikeout rate collapsed to 19% over 52 innings, which is slightly better than Janssen in 2014, by broadly similar (note, Janssen's Year 4 numbers exclude the first month after the ASB)

In the 5th year, they did bounce back somewhat, achieving a 21% strikeout rate over 50 innings. Unfortunately, this is only about 30% of the way back to their previous level. Only 40% of the pitchers got closer to their previous level than their collapse level, with only 6 of 54 (11%) getting within 1% of the previous level or better. On a three year basis, they basically stay around the same level; there's no delayed bounceback.

If Janssen had a similar bounceback in 2014, he'd only end up around 20-21%. If he achieved the same 2.3% bounce, he'd end up around 19%. So, as an expectation, something around league average is about right. Interestingly, a simple 3-2-1 weighting of his K-rate the last three years gives roughly the same result.

We do a similar exercise with FIP, setting a maximum FIP- of 80 for the first three years, and a minimum increase of 20 in the fourth year:

There's a similar picture. An elite group of relievers who had a season where their peripherals collapsed. They were slightly better the year after, but it's best characterized as a dead cat's bounce: after their collapse, they were no longer elite relievers.

So what should be expected of Janssen in 2015? I'd project something like a 19-21% strikeout rate, 5-6% walk rate, a .280 or so BABIP and 8-9% HR/FB ratio. That would make him a good, but not an elite reliever as he was from 2011-13. Given how weak the Jays are in the bullpen from the right side right now, that type of production would be useful at the right price. I would put that price however at no more than something like $3-million/year over maximum two years, with no guarantee of closing. And in this market, that may not be enough even if there was mutual interest in Janssen returning for 2015.