In the first half of the 2013 season Jimmy Nelson was tearing up AA. He struck out nearly 5 batters for every 1 he walked. In 69 innings his ERA was just 2.74 and his FIP was 2.81. He earned a well-deserved promotion to AAA around midseason and started to be talked about as the Brewers #1 prospect.
His 83 innings to close out the year at AAA did not go quite as well. He showed he had the stuff to dominate at the level, striking out roughly the same amount of batters that he had at AA, but his walk rate jumped from 5% of batters to about 14%. His results were reasonable but not anything near good enough to be in line for an MLB promotion.
Clearly, he has found the command this year at the higher level of competition. He's struck out over 28% of the batters he's faced, walked 7%, and given up a home run to .3%. There's a decimal in front of that last 3, representing the fraction 1 out of 301 batters.
If you're of the thought background that Nelson is a pretty good prospect who is having an uncharacteristically good year but might have some control issues and might not immediately be an above-average starter in his first go at the big leagues, it makes sense to consider him and Marco Estrada about equivalent options in the major league rotation at this point.
If you think Nelson is a top prospect who has taken the logical next step of his development and having a dominant season, it makes sense to think of him as an immediate upgrade to the starting rotation.
Nelson turned 25 a few days ago. He's tearing up AAA. He's as ready now as he's ever going to be. He's now thrown around 160 innings at the AAA level. He does have a pattern throughout the minors of struggling with walks when moving up a level. However, leaving him to continue to crush the souls of minor league hitters is not going to help him limit walks when he does get to the big leagues. And for me, when it comes down to it, it's a lot easier for me to see the Brewers actually making 2014 special with a playoff run if Jimmy Nelson is what we think he can be. And I think it's time to start finding out.
I don't look at this so much as Marco Estrada having lost his spot in the rotation as I do Jimmy Nelson forcing his way in and pushing against the only vulnerability. Estrada's peripherals may look fairly good at a glance, but his strikeout and walk numbers have gotten worse in each of the past 3 years and his current FIP is 5.7. Conversation about him getting unlucky due to solid K/ BB numbers must also include reference to the remarkable amount of solo home runs he has given up. He has been able to rack up wins due to providing starts in which he scatters some solo homers. But as we saw on Tuesday night in New York, these things tend to even out over time and are probably not indicative of some sort of skill. He has also stranded 81% of his baserunners this year, a very high number, which is another indicator that he has been fortunate to limit runs given the way he has pitched. He's also a 30-year old with an 88 mph fastball (which has declined 2 mph since 2012).
Marco Estrada has value. The odds are that one of the other 4 starters or Nelson will miss some starts due to injury the rest of the way. Marco will likely be first in line to jump back in the rotation, and hopefully he can work on the control of his changeup in a few lower-leverage innings before moving back into the middle relief role he did well in a few years ago. The problem, of course, will be finding room for everybody on the roster in the next 2.5 months.
Meanwhile, Jimmy Nelson struck out 10 and walked 2 in 6 innings last night. He gave up 1 run. Sounds like as good a game as any to make his final career minor league start.