It would be over the top to call him the Braves' most valuable reliever, but what Jordan Walden has done this year for the team can’t be overlooked. After the season ending injuries to Eric O’Flaherty and Jonny Venters, Walden’s presence in the pen has helped turn many games into seven inning contests. Considering he was picked up in the off-season for Tommy Hanson, whose shoulder is still hanging on for dear life, Frank Wren continues to masterfully assemble young cost-effective bullpens.
Walden’s 0.7 fWAR is second among relievers to none other than Craig Kimbrel. His pre-All-Star Break numbers were stellar, putting up a 2.35 ERA/2.18 FIP/3.54 xFIP slash in 30.2 IP. He has maintained a career level strikeout rate, 28%, while dropping his walk rate from 10.5% to 7.2%, which are all obviously great signs. Walden is a "relief ace" type of pitcher with "closer" abilities, also known as someone who is highly effective at getting out hitters on both sides of the plate.
One noticeable thing about 2013 is that Walden has gone back to a changeup he basically scrapped in his minor league days. We have touched on this point a couple of of times here and there throughout the first half. Walden initially talked about this back in April,
"It's time to have a changeup... A lot of hitters have been sitting on my fastball and attacking it. So I needed something that looked the same [as my fastball]." - April 30, 2013
His fastball has gradually lost velocity over the past four seasons. This season's loss could be due to his pre-DL appearances where he was sitting low-mid 90's, pulling his 2013 average down, so we'll have to see how the rest of the season plays out. As for the changeup, the easiest way to see this usage is in two charts below, courtesy of Brooks Baseball. Take a minute to compare the two charts. The top is his pitch selection to batters from 2010 to 2012, and the second is from 2013 (click to enlarge).
As you can see prior to the season, Walden was very fastball/slider heavy to batters from both sides of the plate, rarely mixing in his changeup to left handed batters. This season has been a much different story. Overall, he has thrown a changeup almost a quarter of the time to lefties, essentially replacing his fastball. Not only is he throwing it more, but it has been effective, receiving whiffs over 30% of the time. It is hard to know without talking to hitters who face him, but it wouldn't surprise me if Walden's leap towards the plate makes the pitch that much more deceptive.
Why is this adjustment and improvement so important? We can take these notes from the FanGraphs library about certain pitches and their splits…
"The general rule of thumb is that pitches that move horizontally (e.g. sliders) work best against same-handed hitters, while pitches that move vertically (e.g. curves, changeups) are most effective against opposite-handed hitters."
These are generalizations and can be tweaked for individual pitchers, but Walden looks to be leveraging each pitch effectively this season depending on the batter handedness. By seeing him increase the usage of both of his great off-speed pitches, paired with a fastball that has sat between 96-98 mph since returning from the DL, it is easy to understand why he has been so dominant.
Going forward, I would expect more of the same. If his shoulder can remain healthy and he can keep the feel for his changeup, the Braves will continue to have one of the best eighth and ninth inning combos in the game. His HR/FB% (2.5%) could see a bit of a correction, but as long as the control is there, expect similar strikeout and walk rates. Because he no longer touches 100 on a regular basis – "just" mid-to-upper 90’s – being able to add an additional off-speed pitch will prove to be even more beneficial if his velocity continues to gradually decline.