Johan Oviedo's Fastball Changes the Shape of His 2026 Outlook

[Jack Lindsay]

To the surprise of many, the Boston Red Sox went out and acquired another starting pitcher in Johan Oviedo, deemed to be more of a project than the previously-acquired Sonny Gray. With 12 years of big league experience, Gray has significantly more predictability in the results department. Fans may look at Oviedo’s last full season with puzzlement, seeing a 4.31 ERA and a 1.37 WHIP in 177 2/3 IP. I am not here to convince you that a 4.31 ERA is anything to write home about, but what I will say is that his fastball and the movement he can generate raise his ceiling significantly.

His fastball is by far his most lively offering. Our own @Nick John spoke of its effectiveness saying,

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“His fastball was impressive during his short 2025 season thanks to it reaching an average of 95.5 mph paired with nearly six inches of tailing action. In a short sample last season, Oviedo also demonstrated an ability to limit hard contact, as his average exit velocity (87.6 mph), hard-hit percentage (35.3%) and barrel percentage (6.9%) would have ranked in the upper-third of the league had he qualified.”

 

The cause of these fantastic numbers is why the Red Sox have sought out Oveido’s services in 2026, and it's why Craig Breslow believes he can be an impact starter; that fastball has a chance to be special.

When checking out Oviedo’s FanGraphs page, you can see a significant jump in his Stuff+ metric and specifically on his fastball. In his last season before Tommy John surgery, Oviedo’s fastball was graded as a well-below-average pitch with a Stuff+ of 82. In 2025, that number jumped an unprecedented 33 points to a Stuff+ grade of 115. Thanks to @TJstats on Twitter, we can get an in-depth look and visual of why Oviedo’s fastball gave hitters problems in 2025.

We can see here that Oviedo’s motion creates a unique profile of release height (hRel) and extension (Ext.), and according to Baseball Savant, his 7.4 feet of extension was in the 98th percentile in MLB. With those specific metrics, it creates one of the most unique fastball profiles in baseball.

With a low release point, fastballs will typically run more horizontally than his does. Think of former Red Sox pitcher Chris Sale. Sale’s release height is .1 feet higher than Oviedo’s, and yet, Sale’s fastball runs 10 inches more than Oviedo’s (15 v. 5.6). Hitters go in expecting this movement as well, and as a result, this creates an effective fastball. Oviedo raised his release height from 2.5 feet to 3.1 feet and, in turn, increased his swinging strike rate from 7% to 10.2%

You can see the release height increase visualized here:

One concept breaking into the mainstream is Induced Vertical Break (iVB). What iVB attempts to do is take gravity out of the equation to determine how well a pitch can combat the effects of gravity and stay up. This used to be looked at publicly through spin rate; if a pitcher’s spin was high, then the fastball would have apparent “rise.” This can now be articulated through iVB — the higher it is (on fastballs), the better chance hitters have to swing underneath the pitch.

Now, Oviedo’s iVB at face value is a below-average level offering, only 15.4 inches, which is -0.6 inches below the average. For comparison, the leader in iVB is Alex Vesia with 20.9 inches.

But because of the combination of release point, arm angle, and iVB, Oviedo was able to increase his fastball K% from 16.1% all the way to 30.9%. His seam manipulation has caused significantly less run to the arm side, and it’s staying up far longer than opposing hitters expect.

Below, his 2023 fastball (left, red) compared to his 2025 fastball (right, red).

In 2023, Oviedo had a fastball that was well below average in terms of rise, as indicated by the shaded circle on the graph. By 2025, he was right at, if not above, league average with his fastball.

Because of this sudden rise and hitters swinging underneath the fastball thanks to the uncanny iVB, his fastball’s fly-ball rate shot up from 25.4% to 58.1%, its zone contact percentage went from 90.2% down to 75.7%, and opposing hitters posted a mere .638 OPS against it.

There’s a reason Craig Breslow said,

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“Sure, he hasn’t yet put it all together in the form of a single dominant season, but that doesn’t mean he can’t or won’t. We’ve seen enough to recognize that he’s got plenty of raw stuff and at 27, there’s development ahead of him.” - MassLive.com

 

At this point, Breslow and Andrew Bailey have done enough to prove that they can identify potential, and with Oviedo, there is a clear foundation of potential at the individual pitch level.

Of course, one glaring issue is the walk problem. Oviedo had a walk rate of 13.5% and has never had a rate below 8.9% in his whole career. It does not matter how nasty of a pitch ball four is.

But beyond that, the prospect of what Johan Oviedo could be is very exciting, and the prospect package was nothing significant for what could be a solid fourth or fifth option in the Red Sox's rotation.

This certainly can’t be the final move for the pitching staff this offseason, but it’s great to see the front office take advantage of farm depth to improve the 26-man roster in two consecutive weeks.

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