For single seasons, From 1901 to 2008, (requiring SO≥150 and At least 85% games in relief), sorted by greatest SO

  Cnt Player             **SO** Year Age Tm  Lg  G  GS CG SHO GF  W  L  W-L% SV   IP   H   R   ER  BB   ERA  ERA  HR  BF   AB  2B 3B IBB HBP  SH  SF GDP  SB CS Pk BK WP   BA   OBP   SLG   OPS  OPS   Pit  Str
 ----+-----------------+-------+----+---+---+--+---+--+--+---+--+--+--+-----+--+-----+---+---+---+---+------+----+--+----+----+--+--+---+---+---+---+---+---+--+--+--+--+-----+-----+-----+-----+----+----+---- 
    1 Dick Radatz         181   1964  27 BOS AL  79  0  0   0 67 16  9  .640 29 157   103  44  40  58   2.29  168 13  635  553 19  5   9   7   9   7   5  10  7  0  0  1  .186  .269  .309  .578   62           
    2 Mark Eichhorn       166   1986  25 TOR AL  69  0  0   0 38 14  6  .700 10 157   105  32  30  45   1.72  248  8  612  548 23  3  14   7   9   2  12  15  5  0  1  2  .192  .261  .288  .549   47           
    3 Dick Radatz         162   1963  26 BOS AL  66  0  0   0 58 15  6  .714 25 132.1  94  31  29  51   1.97  191  9  541  468  8  2  13   5  14   3   5   5  2  0  0  5  .201  .285  .284  .569   62           
    4 Brad Lidge          157   2004  27 HOU NL  80  0  0   0 44  6  5  .545 29  94.2  57  21  20  30   1.90  229  8  369  328  6  4   5   6   3   2   5   2  5  0  1  3  .174  .254  .290  .544   43 1466  983 
    5 Dick Selma          153   1970  26 PHI NL  73  0  0   0 47  8  9  .471 22 134.1 108  42  41  59   2.75  146  8  552  478 16  1   9   4   9   3  10   8  8  2  1 10  .226  .314  .314  .628   75           
    6 Rich Gossage        151   1977  25 PIT NL  72  0  0   0 55 11  9  .550 26 133    78  27  24  49   1.62  243  9  523  459 11  0   6   2   7   6   7   9  3  0  0  2  .170  .250  .253  .503   38           

Seasons/Careers found: 6.

 Photos from the George Grantham Bain Collection at the Library of Congress.