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Strikeout rates and our revamped bullpen

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Rich Lederer continued his look at how batted ball types and strikeouts effected pitchers effectiveness last season. This time he narrowed his focus to relievers, and may have uncovered something surprising. Based on only last year, ground ball rates appear to have almost no effect on relievers ERA. Strikeouts are what matter most.

This is important, as you may have already guessed, because of the type of arms Kenny Williams acquired this off-season. Highlighted as an outlier in the upper right quadrant of Rich's graph is the White Sox closer Bobby Jenks.

  • Mike MacDougal missed the cut, but looking at his rate stats from '06, he would have been holding hands with Cla Marideth on the graph. MacDougal's strikeouts were a little down in '06, and his career stats would put him to be much closer to Bobby Jenks on the graph.
  • Matt Thornton joins Bobby and MacDougal in the best quadrant even though he nearly went a month without striking out a batter in '06.
  • David Aardsma was about two steps to the good side of the K/BF line in '06, and that could increase if Coop can help him cut down on the walks.
  • Nick Masset obviously didn't have enough innings at the major league level to qualify. And the truth is he probably doesn't have enough innings thrown from the pen in the minors to make a judgment solely on the numbers. What we do know about Masset is that he threw a ton of groundballs (3:1 G0/AO) as a starter in '05, but didn't strike out a whole lot of batters. His groundball ratio dropped in '06, but it was still rank very highly (a Bobby Jenks-like 58%) and his K-rate jumped when he took to the pen. This trend continued in winterball where he posted a 22:2 K/BB ratio. Based on these numbers and the scouting reports, I think it's safe to say that Kenny wasn't just blowing smoke when he compared Masset to Jenks.
  • Andy Sisco's GB rate has remained a little below average in each of his major league seasons, but his K/BF% dropped from 23.1% in '05 to 18.7% in '06. Sisco's fastball was down a couple miles an hour in '06, but more importantly, he control was terrible. He walked nearly the same number of hitters each season, but he faced 15.5% fewer batters in '06. Even with his terrible walk rate, Sisco found himself as the last pitcher included in the Southeast quadrant. Again, a little coop magic and he should be safely on the good side of average.
  • Boone Logan should fall safely in the Southeast quadrant once he finally gets used to pitching in parks with capacities exceeding 30K. He struck out over 12 batters per nine innings pitched in Charlotte, and almost 14 per nine after July 1st. The talent is there with Logan, he just has to get his head around being a major league pitcher.
  • Charlie Haeger's knuckler keeps the ball in the park, but his GB% last year in Charlotte (46.3%) is around league average, which might indicate that he won't be able to sustain the ability to keep the ball in the park in the Bigs. Also, his K-rate in Charlotte was rather pedestrian, but it was good in his limited time with the Sox. As a knuckleballer, Haeger is probably the one pitcher who breaks the mold, and should be compared using this model. We should just let the results speak for themselves.
That's 8 relievers, 7 of whom figure to fall on the right side of the graph in '07, under Sox control for at least the next three seasons. Too bad they're so damn affordable.