Mike Foltynewicz’s future role for the Atlanta Braves is still in doubt. He brings a high-90s four-seam fastball that should play well out of the bullpen or as a starter, but his secondary offerings might not be good enough to consistently get hitters out at the Major League Baseball level. Acquired in a trade for Evan Gattis in the offseason, Foltynewicz has started two games for the Braves this season after 16 bullpen appearances for the Houston Astros last season. Results have been mixed thus far. In 10 1/3 innings this year, Foltynewicz has struck out nine but walked six, giving up seven runs and averaging an unsustainable 19 pitches per inning. Foltynewicz will need to be more efficient if he is to remain a starter, and the increased use of his sinker his second start of the season provides him with weapons to get quicker outs, more strikes, and help set up his big fourseam fastball and still-developing slider.

Foltynewicz’s fourseam fastball has been the 23-year-old’s bread and butter, sitting “95-98 mph and has hit 100 mph as a starter” per Kiley McDaniel’s write-up in his analysis of the Braves prospects. Last season in relief, Foltynewicz used his fastball roughly 50% of the time, averaging 98 miles per hour out of the bullpen, per Brooks Baseball. He mixed in a curve, sinker, and change, but did not throw any of those offerings more than one quarter of the time.

In his first start of the season against the Cincinnati Reds, he relied on his fastball even more than 2014, throwing 60 four-seam fastballs among his 94 pitches. He might not have had the feel for his change as he threw that pitch just four times in the outing, mixing in a curve and sinker for his remaining pitches. For Foltynewicz’s four-seamer to be successful, it likely needs to stay up in the zone to get swings and misses. Here is the pitch plot from his first start.

Notice all of those black squares, mostly in the upper half of the strike zone? That is where Foltynewicz lived in his first start with fewer pitches low in the zone or below the knees. When the pitch is working well, he is inducing swings and misses up in the zone like on this strikeout of Todd Frazier.

Hitters have swung at nearly 75% of pitches when Foltynewicz pitches in the zone so far this season, in the top 10% of pitchers with at least 10 innings this year. When he can get the swing and miss, his fastball is great, but hitters can catch up to a fastball when they know what is coming. In his start against the Reds, hitters began to make hard contact with the fastball, but the damage was limited. Here is a first-pitch fastball to Zach Cozart.

That pitch went for an out, but when the four-seamer has the potential to get hit for damage. Here is another four-seamer, this one an out against Jay Bruce when the four-seamer was slightly lower in the zone.

In his next start, against the Phillies, he made the same pitch to Ryan Howard and was not as lucky.

Mixed in with Howard’s home run were seven strikeouts and three walks. Foltynewicz made adjustments from his first start to his second start, changing his repertoire significantly, per Brooks Baseball.

Game Fourseam Sinker Change Slider Curve 5/1/2015 60 10 4 0 20 5/6/2015 41 30 2 18 10

Foltynewicz has not felt comfortable enough with his change in either start to put it to much use. Foltynewicz used a slider, which he had been working on, and it is possible that some of the curves from his first start might have been less than sharp sliders. Eleven of the 18 sliders in his second start went for strikes and he used it to finish off four of his six strikeouts, like this one against Freddy Galvis in the first inning.

Foltynewicz also used his sinker more often, upping the total from 10 pitches in his first start to 30 in his second. In a recent FanGraphs Audio podcast, Kiley McDaniel mentioned to Carson Cistulli (Go to 35:20 for a five-minute discussion of Foltynewicz) that the two-seamer had potential, but had been underused. There was also some discussion that Foltynewicz had trouble finishing his curve/slider in his first start of the year. His pitch plot against the Phillies differed from his first start.

There are still a lot of black squares up and out of the zone representing his four-seam fastball, but the addition of the red squares show that the slider looked to make it into and out of the zone, leaving few to the third base side. There are also more sinkers down in the zone, indicated by the grey boxes. By relying principally on the fourseam fastball, Foltynewicz loses the lower half of the strike zone, but incorporating a hard, sinking fastball, the lower half of the zone becomes a more viable option.

The sinker is not a big swing and miss pitch in general and the same has been true for Foltynewicz thus far, getting just three whiffs on 40 sinkers. However, the sinker does serve an important purpose because the pitch can be thrown for strikes low in the zone, inducing swings and ground balls which can help efficiency and limit damage. The pitch is not much to look at, but low in the zone at 95 miles per hour is not likely to elicit a lot of extra base hits. Foltynewicz used the sinker with two outs and two runners on in the first pitch of the at bat to Cody Asche to get out of the fifth inning in his last start.

Foltynewicz is still a work in progress. The curve can be a good pitch for him at times, and he had the slider working against the Phillies, but he has not yet had the confidence in change and he cannot rely solely on his fourseam fastball to get hitters out without driving his pitch count up and risking major damage. Increased use of his sinker could help him stay in the rotation as he seeks to refine his breaking pitches and continue to use his high-velocity fastball up in the zone for strikeouts. Foltynewicz needs to improve, but there is some room for optimism that he could forestall a move to the bullpen by mixing up his fastballs and becoming more consistent with his slider.