Tigers' Bruce Rondon could benefit by mixing in his changeup

There was a time when the future of the Detroit Tigers bullpen seemed to revolve around Bruce Rondon. And yet, three years on, he was called up as almost an afterthought. The team no longer needs Rondon to anchor the bullpen, but they do need all the depth they can in their relief corps. The flame-throwing righthander could be the piece that turns a good unit into a great one.

One of the key weaknesses of the Tigers' bullpen this season has been the lack of strikeouts. In 77 1/3 career innings pitched in the major leagues, Rondon has a 25.9 percent strikeout rate. His swing-and-miss ability is a welcome addition to a Tigers pen that has only struck out 19.7 percent of hitters this season, ranking 28th among MLB teams. So far in 2016, Rondon has that strikeout rate all the way up to 30.4 percent. He doesn't have the innings to qualify, but Rondon would rank 25th among all relievers, right behind Orioles closer Zach Britton.

Rondon's calling card has always been velocity, and he appears to have recovered from UCL surgery with the full throttle intact. His fastball has averaged 98.46 miles per hour so far, ranking him among the hardest throwers in the game. On top of that, Rondon produces good extension out of his delivery, giving him a perceived average velocity of 99.0 miles per hour.

The spin rate on Rondon's four-seam fastball is almost exactly the major league average of 2240 rpm. As a result, he gets decent rising action and a bit of tail, but the movement is not what you would call electric. Still, in terms of velocity and movement, Rondon's fastball is every bit the equal of Noah Syndergaard's four-seamer, for example. Rondon is capable of dealing one of the best heaters in the game. The issue is inconsistency. The averages paint a picture of a fastball with decent life at the plate, but as we have seen, there are outings where it is quite hittable.

To back up the fastball, Rondon also packs a nasty slider. In his short major league career, Rondon's slider has an outstanding whiff rate of 25.4 percent. Opponents have posted a woeful .335 OPS against the slider in parts of three seasons. The Yankees' Michael Pineda is another pitcher with an elite slider, one that proves a pretty good comp for Rondon in terms of velocity and movement. Pineda has posted a similar career whiff rate with the slider, at 25.2 percent.

While there are plenty of variations in movement and velocity that can make for a good slider, Rondon definitely has one. Paired with velocity few in the game can match and you have the makings of a fine reliever.

Unfortunately, having great stuff isn't enough if the command isn't consistent. That has always been Rondon's weakness. This year, however, the walks have not been a problem. Rondon has walked just five hitters in 17 2/3 innings. He is throwing more strikes, and has moderated the misses to a degree.

Instead, like a lot of American League pitchers over the past year, his home run totals have ruined his numbers. And that damage has been done mainly against his fastball. It's certainly possible that this is just a fluke. We're talking about four home runs in 17 2/3 innings this season. Rondon has never had a home run problem before, and over his career, his numbers have been consistent whether he has runners on base or not. With a league average home run rate, xFIP predicts an ERA of 3.86 for Rondon. The issue is suppressing the hard contact more effectively.

To help in that goal, let's take a look at Rondon's final offering, his rarely used changeup. Rondon has only thrown it 5.3 percent of the time. He broke into the league in 2013 using it twice as often. This is the pitch that could take Rondon from an occasionally good, but erratic reliever into a much higher tier. It certainly has potential to be a weapon, as Mariners third baseman Kyle Seager can attest.

That changeup fades nine inches to Rondon's arm side, with vertical movement of less than six inches. He misses McCann's glove by half a foot, yet, having to guard against the fastball, Seager is well out ahead and looking to turn on what initially looks like a fastball on the inner edge of the plate.

Rondon can throw the changeup anywhere from 87 to 91 miles per hour, and that movement is better than most sinkers you will see. You'd love to see Rondon get more tail on his four-seamer, and throwing the change could help him learn to impart a little more sidespin on the fastball as well. Paired with that explosive fastball, Rondon has an extremely difficult set of pitches for a left-handed hitter to deal with if he'd use the changeup a little more. Against a righthander, the changeup acts like a diving sinker coming from the same arm speed and release point as his four-seamer

One reason I'm emphasizing the changeup is that the Tigers have several pitchers who have made huge strides with the pitch in 2016. Michael Fulmer and Matt Boyd, in particular, have each shown surprisingly good off-speed pitches to pair with their fastballs. Fulmer's changeup seemingly developed overnight into a high quality major league offering, and now he's the AL's ERA leader. It's hard to know how much credit pitching coach Rich Dubee deserves, but we've seen enough to speculate that he has some facility in teaching the pitch.

If Rondon would pitch backwards a little more often, showing hitters the changeup instead of the blazing fastball they expect, it would help keep them off the fastball for those times when he misses in the strike zone. As Dubee has emphasized to the whole staff, he would like guys like Rondon pitching on the inside edge to keep hitters jammed and uncomfortable. Fastballs up and in, with a tight, hard slider low-and-away to right-handed hitters, or down-and-in to left-handed bats, is a fine recipe for success. Mixing in the changeup  would be wrinkle that makes an already fine arsenal a great one.