Blue Jays: Is Rowdy Tellez the First Baseman of the Future?

ST PETERSBURG, FLORIDA - SEPTEMBER 06: Rowdy Tellez #44 of the Toronto Blue Jays reacts after striking out to Cole Sulser #71 of the Tampa Bay Rays in the eighth inning at Tropicana Field on September 06, 2019 in St Petersburg, Florida. (Photo by Julio Aguilar/Getty Images)
ST PETERSBURG, FLORIDA - SEPTEMBER 06: Rowdy Tellez #44 of the Toronto Blue Jays reacts after striking out to Cole Sulser #71 of the Tampa Bay Rays in the eighth inning at Tropicana Field on September 06, 2019 in St Petersburg, Florida. (Photo by Julio Aguilar/Getty Images) /

Rowdy Tellez has an opportunity to become the Toronto Blue Jays first baseman of the future. Is he capable of meeting that challenge?

Rowdy Tellez made his MLB debut on September 5, 2018. He had a terrific first month in the big leagues: his wRC+ was 151 and he posted a 0.5 fWAR. Unfortunately, 2019 has been a struggle compared to his initial campaign. To date, his wRC+ is 85 and his fWAR is negative 0.2.

Can Tellez be the first baseman of the future?

The opening question can be best answered by completing the following steps:

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  • Review Tellez’s various career metrics and compare them to MLB first basemen
  • Examine percentile points of selected metrics of MLB first baggers
  • Determine what numerical improvements that he would need to generate in order to reach various targets
  • Examine what change(s) Tellez would need to make in order to reach the targets noted above
  • Draw a conclusion

Data for the 2019 season includes all 2019 games up to and including the games of September 11th. This article will focus strictly upon Tellez as a hitter.

Career metrics

Table 1 illustrates some of Tellez’s career metrics and where they rank in terms of percentiles. The sample consists of all first basemen/designated hitters, with a minimum of 600 plate appearances, during the 2018-2019 period. It should be noted that the higher the percentile the better. The highlights are as follows:

  • Tellez’s BB% (5.6), K% (28.8), and BB%-K% (negative 23.2) are 7th, 9th, and 7th percentile, respectively
  • His OBP is 0.291, which is 9th percentile
  • He has recorded a 97 wRC+
  • His SLG% is 0.474, which is 58th percentile

The 2019 season

Table 2 highlights some of Tellez’s 2019 season to date and also the period after his stint in Buffalo. Other than BABIP and batting average, there has been a slight uptick in Tellez’s performance after his return from the Bisons.

MLB first-basemen – 2018 to 2019

Table 3 showcases the percentile/quartile breaks for various metrics of first basemen during the 2018-2019 seasons.

Numerical improvements needed to reach sundry target levels

Table 4 highlights the numerical improvements that Tellez needs to attain in order to reach different targets: median; top-third; first-quartile; and top-ten%.  Some targets of note include the following:

  • A 5.3 percentage point increase in BB% for Tellez would place him at the median
  • If Tellez could reduce his K% by 10.0 percentage points, he would be at the first-quartile mark among first baseman
  • A 15.9 percentage point increase in the BB%-K% metric would vault Tellez into the top-quartile level
  • A better BABIP would improve his BA. However, he cannot rely solely on a change in luck to realize an improved batting average
  • If Tellez were to become a first-quartile OBP first baseman, he would need to add 73 percentage points; that necessitates a better BB% and BA

Required Change

Compared to other first basemen/designated hitters, Table 5 captures the Tellez story:

  • He swings at a lot of pitches that are not in the strike zone
  • He doesn’t swing at a lot of pitches that are in the strike zone
  • When he swings, he misses at a high rate, particularly on hard stuff (fastballs)
  • He is almost top-quartile in xBA on fastballs hit, which is good
  • He is 85th percentile in xSLG on fastballs hit, which is excellent

According to Brooks Baseball, his pitch-type breakdown is as follows: hard stuff – 52%; breaking – 33%; and off-speed – 15%.

A tip of the cap to Jim Scott, who pointed me towards Brooks Baseball for the breakdown between hard, breaking, and off-speed pitches.

Can Tellez hit a fastball?

As I began the data collection for this article, one of my initial thoughts was that Tellez had difficulty handling the fastball. This was partly based on my recollection of comments expressed by Keith Law, ESPN’s baseball writer and former Blue Jays executive during the J.P. Ricciardi regime. However, I discovered two things that disproved my perception of Tellez and fastballs

  • His almost first-quartile xBA and elite xSLG on hard stuff belies that preconception. You cannot profile as a batter that is overwhelmed by a fastball if you generate the exit velocity and launch angle on fastballs required to excel in xBA and xSLG.
  • Out of 45 first basemen/designated hitters, Tellez is 31st highest in terms of the percentage of pitches thrown to him that are fastballs. Given the advanced state of data collection and video, he would not rank so low in this metric if opposing MLB pitchers had determined that Tellez could not hit a fastball.

Plate discipline

I think this is the area that Tellez must address if he is to be the Blue Jays first baseman of the future. Better plate discipline is better strike-zone awareness. This can lead to taking more pitches that are out of the strike zone thereby reducing the O-Swing% metric. By forcing pitchers to throw strikes, Tellez should see improvements in his BB%, K%, BA, and OBP (all things being equal). If he can produce a better SLG%, we should see a better OPS. This is all theory, but I find it difficult to believe that better plate discipline would not derive better performance in the noted metrics.

Well, is there a specific plate discipline aspect that Tellez can address? Yes. Stop swinging at fastballs out of the strike zone!  In terms of plate discipline, a comparison to Eric Thames is in order. Table 6 illustrates that Thames is better than Tellez at not swinging at pitches outside of the strike zone. Thames has also produced a better OBP and OPS than Tellez in 2019.

A comparison of Image 1 and Image 2 leads to the conclusion that Tellez swings at more fastballs out of the strike zone, particularly high ones, than Thames. Image 3 and Image 4 shows that Tellez is marginally better-disciplined than Thames when facing breaking balls. So, all is not lost for Tellez. However, he should lay off the high, out-of-zone fastball!

As Table 5 illustrates, Tellez’s relative pitch-type weakness is breaking balls. His lowest xBA and xSLG is on breaking balls compared to hard stuff and off-speed pitches. Perhaps a combination of better plate discipline and pitch recognition can lift his performance on breaking balls. However, this is purely a guess on my part.


A University of Virginia Law School professor said to a graduating class, “Three years ago, when asked a legal question, you could answer, in all honesty, ‘I don’t know.’  Now you can say with great authority, ‘It depends’”.

After analysing Tellez, I feel like a graduating law student. Is Tellez the Blue Jays first baseman of the future? It depends. Certainly there are some positive aspects to his hitting, namely his xBA and xSLG on fastballs, and his Barrels% is higher than the MLB average. On the negative side, he is a slow runner (16th percentile per Statcast) and he has shown little plate discipline to date.

Table 7 presents some scenarios to consider. For example, if Tellez were to have 595 plate appearances, a 10.9 BB%, and other assumed stat lines, he would produce a 0.268/0.348/0.487 slash line. That 0.835 OPS would rank in the 63rd percentile in 2019. That would be a fine OPS for Tellez, but can he do it? I am not sure.

However, given that Tellez has accumulated fewer than 500 plate appearances in his MLB career, my view is that it is too soon to reach any definitive conclusion regarding how he projects as a first bagger. We need the 2020 season to have a better idea of what his expected performance level will be.

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The last word

Rowdy Tellez came into the Major Leagues and briefly excelled. However, the 2019 season has cast some doubts regarding whether he is the future first baseman for the Blue Jays. As clichéd as it sounds, time (the 2020 season) will tell.