Back in the day, I lived within a couple hours of the Cubs AAA affiliate. I didn’t go to many games, but I followed them close enough to know when a good player was in town, either with the Des Moines Cubs or a visiting team. In the process, I began to kind of dig the Cubs minor league system. Back then the Cubs were not great, and the Indians were not too hot either, so I never really saw the Chicago organization as a threat. It was easy to root for their players, and I followed a bunch as they moved on with the Major League careers.
Sean Marshall was one of those. He was drafted by the Cubs in 2003, their 6th round pick out of Virginia Commonwealth. It proved to be a great selection, and by 2005 he was the Cubs #6 prospect. He has some injury issues but projected to be a middle of the order starter or excellent reliever.
He made the majors in 2006, but struggled in a starting role. Over 125.2 innings he allowed 132 hits while striking out 77 and walking 59–good for a 1.520 WHIP/83 ERA+. He returned to the rotation in 2007 and was a little better, going 7-8 with a 3.92 ERA/1.374 WHIP/118 ERA+.
By 2008 the Cubs transitioned Marshall to a relief role, and he blossomed into one of the better bullpen arms in the National League. From 2008 to 2011 Marshall averaged 75 innings and carried a 3.29 ERA/1.236 WHIP/131 ERA+. Over 301 innings he allowed 275 hits while striking out 295 batters.
He was traded to the Reds in December 2011. He would have a fine season in 2012–on par with his career averages. Unfortunately, that was his last full season in the majors. He struggled with injuries in 2013 and 2014, pitching a combined 24 innings over those two years, and was out of baseball by 2015.
| Year | Age | Tm | Lg | W | L | ERA | G | GS | GF | CG | SHO | SV | IP | H | R | ER | HR | BB | IBB | SO | HBP | BK | WP | BF | ERA+ | FIP | WHIP |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2006 | 23 | CHC | NL | 6 | 9 | 5.59 | 24 | 24 | 0 | 0 | 0 | 0 | 125.2 | 132 | 85 | 78 | 20 | 59 | 3 | 77 | 7 | 0 | 6 | 563 | 83 | 5.57 | 1.520 |
| 2007 | 24 | CHC | NL | 7 | 8 | 3.92 | 21 | 19 | 0 | 0 | 0 | 0 | 103.1 | 107 | 52 | 45 | 13 | 35 | 3 | 67 | 1 | 0 | 4 | 446 | 118 | 4.62 | 1.374 |
| 2008 | 25 | CHC | NL | 3 | 5 | 3.86 | 34 | 7 | 6 | 0 | 0 | 1 | 65.1 | 60 | 28 | 28 | 9 | 23 | 4 | 58 | 4 | 0 | 3 | 279 | 119 | 4.39 | 1.270 |
| 2009 | 26 | CHC | NL | 3 | 7 | 4.32 | 55 | 9 | 10 | 1 | 0 | 0 | 85.1 | 91 | 43 | 41 | 10 | 32 | 4 | 68 | 1 | 0 | 2 | 373 | 103 | 4.19 | 1.441 |
| 2010 | 27 | CHC | NL | 7 | 5 | 2.65 | 80 | 0 | 16 | 0 | 0 | 1 | 74.2 | 58 | 25 | 22 | 3 | 25 | 5 | 90 | 2 | 0 | 1 | 307 | 160 | 2.28 | 1.112 |
| 2011 | 28 | CHC | NL | 6 | 6 | 2.26 | 78 | 0 | 18 | 0 | 0 | 5 | 75.2 | 66 | 21 | 19 | 1 | 17 | 4 | 79 | 2 | 1 | 0 | 307 | 173 | 1.86 | 1.097 |
| 2012 | 29 | CIN | NL | 5 | 5 | 2.51 | 73 | 0 | 22 | 0 | 0 | 9 | 61.0 | 55 | 18 | 17 | 3 | 16 | 2 | 74 | 3 | 1 | 1 | 256 | 165 | 2.24 | 1.164 |
| 2013 | 30 | CIN | NL | 0 | 1 | 1.74 | 16 | 0 | 3 | 0 | 0 | 0 | 10.1 | 4 | 3 | 2 | 0 | 2 | 0 | 10 | 1 | 0 | 2 | 37 | 225 | 1.98 | 0.581 |
| 2014 | 31 | CIN | NL | 0 | 0 | 7.71 | 15 | 0 | 4 | 0 | 0 | 0 | 14.0 | 23 | 14 | 12 | 1 | 12 | 0 | 14 | 2 | 0 | 1 | 80 | 49 | 5.06 | 2.500 |
| 9 Yr | 9 Yr | 9 Yr | 9 Yr | 37 | 46 | 3.86 | 396 | 59 | 79 | 1 | 0 | 16 | 615.1 | 596 | 289 | 264 | 60 | 221 | 25 | 537 | 23 | 2 | 20 | 2648 | 114 | 3.84 | 1.328 |
| 162 | 162 | 162 | 162 | 6 | 7 | 3.86 | 59 | 9 | 12 | 0 | 0 | 2 | 92 | 89 | 43 | 39 | 9 | 33 | 4 | 80 | 3 | 0 | 3 | 396 | 114 | 3.84 | 1.328 |