Doctoring The Numbers: Byung-Hyun Kim

Byung-Hyun Kim arrived on American soil last spring and brought a
new pitch, the submarine slider, with him. This year, he’s proving that his
cup of coffee last season–just 20 hits allowed in 28 innings while
striking out 31–was no fluke. Though he lost the Diamondbacks’ game on
Sunday, allowing his first home run of the season in the process, Kim has a
2.03 ERA in his rookie season, allowing just 15 hits in 27 innings with an
amazing 45 strikeouts.

Kim’s ratio of 15.19 strikeouts per nine innings would be a major league
record for any pitcher with 25 or more innings:

Name             Year      IP     K     K/9

Billy Wagner     1999    74.2   124   14.95
Armando Benitez  1999    78.0   128   14.77
Billy Wagner     1998    60.0    97   14.55
Billy Wagner     1997    66.1   106   14.38
Rob Dibble       1992    70.1   110   14.08

Kim has been so effective that despite his lack of experience, he was used
by Buck Showalter as the Diamondbacks’ closer while Matt Mantei was
on the DL. Kim already has six saves this season, which is significant
because the role of closer is so rarely handed to one so young. Kim is just
21 years old, and closers are almost always 25 or older. In general, any
pitcher with an arm good enough to close at a younger age is still a
starting pitcher.

The most career saves by a pitcher before age 23:

Name             Saves

Terry Forster      70
Billy McCool       48
Victor Cruz        31
Neil Allen         30
Gregg Olson        27

Terry Forster is primarily remembered for his weight and his
offensive prowess, as in "that fat tub of goo can hit." Forster’s
.397 career average in 78 at-bats is a major-league record for anyone with
more than 45 at-bats. But as a rookie in 1972, Forster saved 29 games,
posted a 2.25 ERA and tossed 100 innings without allowing a single home run.

Since 1980, only two pitchers as young as Kim have recorded as many as
eight saves: Mitch Williams, with eight in 1986 and Kelvim Escobar, who
saved 14 games down the stretch for the Blue Jays in 1997. Escobar, of
course, was then moved to the starting rotation the following season and
hasn’t recorded a save since.

In fact, it is rare for a pitcher so young to be used as a reliever,
period. Only 12 pitchers in history have relieved in 60 or more games
before they turned 22. The top six:

Name              Relief Appearances

Billy McCool             154
Terry Forster            143
Victor Cruz               93
Erv Palica                82
Dick Welteroth            81
Mitch Williams            80

Erv Palica pitched for the Dodgers in the late 1940s, and held on
long enough to pitch for the Orioles in 1955-56. Dick Welteroth was
brought to the majors in 1948 by the Washington Senators and quickly
dispelled any notions that he was a major-league pitcher, retiring in 1950
with a remarkable 145 walks and 55 strikeouts.

Kim needs only 56 appearances to crack the top five, and has a chance to
reach the top three before year’s end.

It’s hard to get a sense of what Kim’s future might bring, as history
provides us with so few young, dominating relievers with which to compare
him . But consider this: only three relievers age 21 or younger have
appeared in 50 or more games in a season and struck out at least a batter
an inning: Terry Forster, Billy McCool…and Pedro Martinez.

Hmmm. Maybe Kim’s future shouldn’t be in the bullpen after all.

Rany Jazayerli, M.D., can be reached at ranyj@baseballprospectus.com.