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Pleskoff Scouting Report | Thyago Vieira

Bernie Pleskoff



Seattle Mariners relief pitcher Thyago Vieira throws against the Baltimore Orioles in the ninth inning of a baseball game Monday, Aug. 14, 2017, in Seattle. (AP Photo/Elaine Thompson)
AP Photo/Elaine Thompson
  • TEAM: Seattle Mariners
  • AGE: 24
  • POSITION: Pitcher
  • BATS: Right
  • THROWS: Right
  • HEIGHT: 6-foot-2
  • WEIGHT: 210 pounds
  • ACQUIRED: The Seattle Mariners signed Vieira as an international free agent out of San Paulo, Brazil, in 2010.


The Mariners signed Vieira when he was only 17 and very inexperienced. He was a “raw” pitcher without a feel for pitching and without the mechanics required to succeed.

What has happened since they signed him is a tremendous testament to excellent judgment, excellent coaching and perseverance. I’ll discuss more about that later.

If there were a list of pitchers to help define a “power arm” that list would include Vieira. While he generally sits in the high 90s, he can throw his fastball at 102 to 103 miles per hour. Using a high energy and aggressive approach in his delivery, his pitch explode on the hitter. In my observations, Vieira’s fastball grades as an 80 on the 40-80 scouting scale.

In addition to his fastball, Vieira continues to work on perfecting and refining his primary secondary pitch, his curveball. With a velocity in the mid to high 80s, his curve can change the eye level and alter the balance of the hitter. Think fastball and get curve? That makes it very difficult for the hitter. He can also work it the other way. He can pound a few curveballs and then revert to his best pitch, the fastball. He throws his fastball three-quarters of the time.

There was a time in the Arizona Fall League when I thought I saw him throwing a slider. If, in fact, the slider is still in his repertoire, it will make for a very viable and usable third pitch. Basically, he’s a fastball pitcher with his secondary pitches truly being secondary.

When he began his career with the Mariners, his slider was a prominent second pitch.


When he began in the Mariners organization Vieira had a great degree of difficulty finding the strike zone. Opening up his shoulder and body far too soon, he was the type of pitcher who would get the ball and throw it without any knowledge of proper pitching mechanics. His command and control were in need of total rebuilding. Or better put, he needed to learn how to pitch.

Now, having completed seven seasons in the Mariners organization, it is safe to say that Vieira is coming closer and closer to being a pitcher. His command and control have both improved. His mechanics are much cleaner, and the results are evident. Again, credit the Mariners scouts, coaches and general manager with finding a great arm, refining that great arm and not giving up on that great arm.

In the beginning, Vieira was the type of pitcher who would like to throw the ball through the backstop. He’s the type of guy who trusts his arm, and he wanted to throw every pitch past the hitter. He still needs to refine his aggressive “take no prisoners” approach somewhat, but it isn’t nearly to the point it was when he was a rookie.

When I saw Vieira pitch in the Fall League he was “high effort,” and aggressive to the point of being almost too violent — a term used to describe pitchers with their hair on fire. That approach has tamed somewhat due to the fabulous work of the Mariners coaching staff. He was the hardest-throwing pitcher in the Fall League, as his fastball touched 103 miles per hour on many scouts’ radar guns.

Vieira has to further develop at least one secondary pitch — at this point that would most likely be his curveball — to be a viable bullpen contributor. He is making progress with the pitch, and the hitter can’t just sit on the fastball and hope for the best. He mixes in the curve a third of the time, and he is gaining confidence in his ability to throw the pitch. If he can return to an improved slider it would be very helpful in his hunt for success.

Vieira still has to learn to repeat the same delivery with his curveball that he does with his fastball. He can’t tip his secondary pitches with a change in release point or arm angle.
His command is still not totally refined.


When Vieira began pitching for the Mariners’ Venezuelan Summer League team in 2011 he walked an average of 11 hitters and yielded an average of 11 hits per nine innings. In his 18 innings pitched, he walked 22. He struck out only eight. He repeated the Venezuelan League the following year. In 55 innings, he walked 17 and yielded 67 hits. Had the Mariners made a mistake signing Vieira? Had they wasted $65,000 on a pitcher with a great arm and little clue how to pitch?

Vieira was both starting and relieving in his first two years. He was a starter his third season when he pitched at Short Season Everett in the Northwest League. Then he became a reliever exclusively when he went to Clinton in the Class-A Midwest League in 2014.

Ultimately, the Mariners front office, led by Jerry Dipoto, determined that Vieira’s arm was too good and too valuable to reject. He and the Mariners executives decided to keep Vieira in the organization and let him work with organizational pitching coach Ethan Katz. Katz worked wonders with Vieira. He not only taught him how to pitch, he injected confidence and a work ethic that led to the ultimate goal — success.

I would credit the Mariners coaching staff with not only refining his delivery, but also teaching Vieira how to throw his curveball. It is evident they took Vieira almost from scratch and turned him into a pitcher as opposed to a guy who throws the ball through the wall.

I recently saw Vieira pitch in the Sirius/XM Futures Game in Miami. He threw two-thirds of an inning, yielding a walk and a hit to the first two batters he faced, but he gave up no runs. He faced four batters and struck out one.

Fast-forwarding beyond the Arizona Fall League and beyond pitching at Double-A Arkansas and Triple-A Tacoma successfully, Vieira pitched this season with the Mariners.

Vieira made his major-league debut on August 14 against the Baltimore Orioles in a game the Mariners lost 11-3. He threw the 9th inning and struck out one while throwing ten pitches in a clean inning. He was reassigned to the minor leagues after that outing.


Upside remains for this power arm. Vieira is showing the Mariners he can harness his fastball and improve his curveball. He will have to continue to throw strikes, miss some bats and be able to successfully navigate a major-league lineup. Spring training will be a time for him to carve out a position on the club. It won’t be easy.

Best suited as a reliever, Vieira will face still competition from a long line of Mariners relievers. Their relief depth is among the strengths of the big-league club. The Mariners are deep and solid in that department, making it all the more difficult for Vieira to find a role.

Given his power arm, Vieira can set himself apart with commanding a wipeout fastball. He can help the Mariners, if, in fact, he can get more strikeouts with his high-velocity pitch.

My best guess is that Dipoto will find a new team for Vieira. He is too good a prospect with too strong an arm to continue as a minor-league pitcher. In my opinion, Dipoto can include Vieira in a trade to improve an area of perceived weakness on his team.

If he isn’t traded, the Mariners may try to use Vieira as a starter. I would find that difficult, due to his lack of repertoire. Unless, of course, his secondary pitches prove to be ready for prime time.

In short, should they choose to trade him, Vieira may well fetch a starting pitcher or meet another need for Seattle. If he stays with Seattle, he will have to prove he deserves a role with the parent club.


Vieira is a hard-throwing, right-handed free-agent pitcher from Brazil. Now 24, Vieira was a raw “thrower” before the Mariners coaching staff did wonders with his mechanics and mound demeanor in teaching him how to pitch.

Seven years after he began as a professional pitcher with Seattle, Vieira is on the brink of helping a team out of the bullpen.

Using basically a fastball that can touch 103 miles per hour and a power curveball in the 80s, Vieira must continue to find command and control of all his pitches. With his velocity, he must find a way to gain more movement on his pitches and induce more strikeouts.

With a crowded bullpen, and having almost too many bullpen mouths to feed on one 25-man roster, the Mariners may choose to move Vieira in a trade for starting pitching or for another piece for their roster. That is unless they try to make Vieira into a starter. In my estimation, he doesn’t have a deep enough repertoire for that important role.

SCOUTING PHRASE FOR VIEIRA: Intriguing power-arm pitcher still refining his delivery

SCOUTING GRADE FOR VIEIRA: 45 — Marginal relief pitcher fighting to remain on a roster

Follow me on Twitter @BerniePleskoff

Bernie Pleskoff served as a professional scout for the Houston Astros and the Seattle Mariners. After retiring from scouting, Bernie began writing scouting reports of prospect players for RotoWire.com. He also began a podcast titled Short Hops, which continues today and is featured on iTunes every week. He is a contributing writer to the RotoWire annual Baseball Preview Magazine. Bernie joined the staff of MLB.com and served as a scout/analyst for the site's Pipeline prospect team, contributing multiple scouting reports weekly and providing his personal ranking of prospect players. He writes a continuing blog for MLBlogs.com titled BERNIE'S BASEBALL WORLD in which he analyzes teams and players from a scout's perspective. Bernie is a weekly contributor on the Sirius/XM Fantasy Sports network's RotoWire.com fantasy show each Thursday morning. He has been married to his wife MaLinda for 49 years. They have no children and live in Cave Creek, Arizona.