Taijuan Walker and 60 Percent Bust Rates


Last week, the Mariners tried to trade whom many consider the best pitching prospect in baseball in a package to get Justin Upton, before Upton nixed the trade. I thought the trade was a bad idea, but others didn’t agree. Dave Cameron disagreed that it was an overpay and cited a study that showed the attrition rate for pitching prospects. However, what caught my eye was that there was no mention of Walker’s age and the how young he was for his level in 2012 (and that he was pretty successful, better than league average according to SIERA).

Here is a complete list of pitchers that were age 19 in AA with qualified innings since 2006:

Jordan Lyles (2010)

Taijuan Walker (2012)

Complete list of pitchers that were age 20 in AAA with qualified innings since 2006. Here, we are making the assumption that Walker throws a qualified amount of innings in Tacoma in 2013, which seems pretty likely:

Julio Teheran (2011)

Both of those pitchers have had their up and downs in the Majors so far. I obviously went back further, and looked at pitchers in AA that were 19 with at least 100 innings from 2000-2005:

Edwin Jackson (2003)

Oscar Villarreal (2001)

Jerome Williams (2001)

(C.C. Sabathia threw 90.1 at age 19 in 2000. Matt Cain threw 86 in 2004. Zach Greinke had 53 in 2003. Felix Hernandez was 18 when he threw 57.1 innings in AA!)

There are obviously just 3, and 2 of those were above average pitchers (a positive career WAA) and the other one is Jerome Williams, who has had quite a ride, but Walker is obviously in some company that we just don’t know much about (but one we can expect to be better than the prototypical top pitching prospect). There isn’t a large sample size of pitchers having success in the upper minors at such a young age. This somewhat demonstrates my point. Walker isn’t a guarantee by any means, but in my opinion, he doesn’t fit into the category of 60 percent bust rate.

SiriusXM All-Star Futures Game

As sort of an appendix, I looked at the Baseball America top 100 from 2003 (the last year mentioned in the study linked to above talking about pitching prospect attrition rates) and listed all the pitchers, along with their ages at the time (for ease I just subtracted their current age by 10), level they spent most of 2002 in, and their career WAA.

5. Jesse Foppert, Age 22, AAA, -1.2 WAA

6. Jose Contreras, Age 31, Cuba, 2.7 WAA

9. Gavin Floyd, Age 19, A, 4.6 WAA

10. Francisco Rodriguez, Age 21, AAA, 10.3 WAA

11. Scott Kazmir, Age 18, A-, 6.7 WAA

18. Adam Wainwright, Age 21, A+, 11.7 WAA

20. Jeremy Bonderman, Age 20, A+, -6 WAA

24. John Van Benschoten, Age 22, A,  -4.5 WAA

25. Sean Burnett, Age 20, A +, 2.4 WAA

27. Rafael Soriano, Age 23, AA, 7.2 WAA

29. Rich Harden, Age 21, AA, 9.3 WAA

30. Cliff Lee, Age 24, AA, 18.4 WAA

32. Colby Lewis, Age 23, AAA, -1.2 WAA

35. Jonathan Figueroa, Age 20, RK, No Majors

36. Dustin McGowan, Age 20, A, -2.4 WAA

41. Aaron Cook, Age 23, AA, 4.6 WAA

42. Franklyn German, Age 22, AA, -.4 WAA

43. Dontrelle Willis, Age 21, A, 5.6 WAA

45. Aaron Heilman, Age 24, AA, -2.3 WAA

47. Angel Guzman, Age 21, A+, .1 WAA

50. Jerome Williams, Age 21, AAA, -.6 WAA

51. Ervin Santana, Age 20, A, -1.6 WAA

52. Bryan Bullington, Age 22, A, -.9 WAA

53. Andy Sisco: Age 20, A-,  -.5 WAA

54. Zach Greinke: Age 19, A-, 17.5 WAA

56. Mike Jones: Age 19, A, No Majors

58. Bubba Nelson: Age 21, A+, No Majors

59. Mike Gosling: Age 22, AA, -.8 WAA

60. Bobby Jenks: Age 21, A+, 3.9 WAA

62. Clint Everts: Age 18, A-, No Majors

64. Kurt Ainsworth: Age 24, AAA,  -1.2 WAA

68. Macay Mcbride: Age 20, A, -.8 WAA

69. Bobby Basham: Age 22, A, No Majors

70. Jeremy Guthrie: Age 23, AA, 6 WAA

71. Josh Karp: Age 23, AA, No Majors

73. Kris Honel: Age 20, A, No Majors

74. Dewon Brazelton: Age 22, AA, -6.1 WAA

76. Clint Nageotte: Age 22, A+, -1.4 WAA

77. Chris Gruler: Age 19, A, No Majors

79. John Patterson: Age 24, AAA, 2 WAA

80. Ben Kozlowski: Age 22, A+, -.1 WAA

83. Francisco Liriano: Age 19, A, 1.7 WAA

84. Mark Phillips: Age 21, A+, No Majors

88. Taylor Buchholz: Age 21, A+, .1 WAA

89. Donald Levinski: Age 20, A, No Majors

90. Ben Hendrickson: Age 21, A+, -1.5 WAA

92. Jon Rauch: Age 24, AAA, 2.2 WAA

93. Chin-hui Tsao: Age 21, A+, -.4 WAA

96. Mike Hinckley: Age 20, A-, .7 WAA

97. Jason Arnold: Age 23, A+, No Majors

98. Seth Mcclung: Age 21, AA, -4.4 WAA

99. Edwin Jackson: Age 19, A, 1.4 WAA

There was 21 successes (those above average) out of the 54 pitchers that I counted (38.9%, so a little worse than most years). The average age of those successes was 21.57 years old, while the average age of 54 was 20.56 years old, so the younger pitchers were actually less successful. Of course, this could be an attrition bias, as the younger pitchers are on average at lower levels, meaning they have longer to fail. The average player (excluding Jose Contreras of course) was roughly in A+ on the list. The ones that pitched most of their 2002 innings in A+ or above were successful slightly more than the ones that were below A+. This is interesting, but not very predictive, so I’ll stick to fastball velocity being the best predictor for pitching prospects.

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