[rudel.dietrich]

That is pretty amazing. I wonder how much of it is compensated by low sample size and a poor Indians lineup however.
That is 144 BB per 162 games which is fairly amazing given his age.

However I think Jason Heyward is the best prospect in baseball at the moment in terms of eye and potential eye.
He is on pace for 89 BB per 162

Surprisingly or unsurprisingly that is not anywhere near a record.
Here are the top 5 based on an article from fangraph.com

Here are two lists for most walks by a player 21 or below.

T5. 103 BB by Jimmie Foxx – 1929 Philadelphia, 21-years-old, 638 plate appearances (16.1%)
T5. 103 BB by Mel Ott – 1930 New York, 21-years-old, 646 plate appearances (15.9 %)
3. 107 BB by Ted Williams – 1939 Boston, 20-years-old, 677 plate appearances (15.8%)
2. 113 BB by Mel Ott – 1929 New York, 20-years-old, 674 plate appearances (16.8%)
1. 117 BB by Rickey Henderson – 1980 Oakland, 21-years-old, 722 plate appearances (16.2%)

That is elite company and also shows how underrated Ricky Henderson is. He was great at 21 and stayed great for 20 years.

Anyways, from 1990 onwards here is the list.

1. Ken Griffey Jr. 71
2. Albert Pujols 69
3. Miguel Cabrera 68
4. Delino DeShields 66
5. Ken Griffey Jr. 63
6. Ryan Zimmerman 61
7. Adrian Beltre 61
8. Alex Rodriguez 59
9. Melky Cabrera 56
10. Adrian Beltre 56

Again that is some pretty elite company and Heyward if he continues seeing regular playing time could set or shatter that record by 10-15 walks if he quickens the pace a little.
Barry Bonds by comparison started playing regularly at age 21 and had 65 in 484 PA
Ted Williams had 147 by age 22


Santana needs a full season or at least a half season of data before we can really start to examine him and get a fuller sample size.
I will be keeping an eye on him and seeing how he progresses in the next few years and seeing if this amazing pace keeps up.