In 2014, the Brewers rotation saw some stability that they hadn't seen since the playoff season in 2011. Four pitchers made at least 27 starts, and only seven pitchers made starts. Unfortunately, they didn't see the same stability in 2015. Eleven different pitchers made starts, and only one pitcher had more than 25 starts. That pitcher was Jimmy Nelson, who kept some stability in a rotation that was in flux all season.
Overall, Jimmy Nelson's 2015 season wasn't much different than his 2014 season in the majors. His strikeout rate was only slightly better at 7.51 K/9, but his walk rate jumped to 3.30 BB/9. His ERA did drop from 4.93 to 4.11, but his FIP increased from 3.78 to 4.10. He did lead the team's pitchers with an fWAR of 2.1, but if you project out Nelson's 2014 season to 30 starts, it's about the same as 2014.
When you look at Nelson's month-by-month stats, there are some interesting splits:
Looking at the stats, July was his best month. His ERA is a bit misleading at 1.64 (he allowed ten runs, four of those unearned), but the FIP and batting line back up that as his best month. His first few months were up and down, then he put together that good July before he saw a rough end to the season. Even though he had a bad end to the season, the FIP suggests that it wasn't as bad as it looked. It's also important to note that this was his first full season in the majors, and the rough end could have just been related to him tired from the rigors of a full season.
Nelson's best value in 2015 came from the stability that he gave the rotation. As mentioned earlier, Nelson was the only pitcher to make over 25 starts in 2015. Meanwhile, the rest of the rotation to start the season each went down one by one. Mike Fiers was traded to Houston at the end of July, then Kyle Lohse was removed from the rotation at the start of August. Wily Peralta missed two months with a rib injury, and Matt Garza missed two and a half weeks with shoulder tendinitis and then was removed from the rotation in September. Nelson was the only starting pitcher who was there every five days from opening day into September.
Unfortunately for Nelson, his season also came to an early end. On September 17, he was hit in the head by a batted ball and left the game early. After spending a few days in the hospital, he was cleared medically and could have returned to the rotation. However, with only a few weeks left in the season and nothing to play for, the team decided to shut Nelson down for safety.
Looking ahead to Nelson's future, he is under team control for the next five years. He should receive the team minimum in 2016 and 2017 before hitting arbitration in 2018. Having a player of Nelson's caliber at a salary that low for the foreseeable future will be important as the Brewers continue to rebuild, and Nelson is a candidate to be the #1 starter in the rotation to begin 2016.