Brad Boxberger had an excellent year in 2014. With Jake McGee out of the picture for the beginning of the 2015 season, the California native may have a good chance to claim the closer spot, at least for now. The question then is, can he get it and what we can we expect for 2015?
As we are now in full Spring Training mode and still a few days off from the first exhibition games, let's have a look at Boxberger metrics in the past year and see how well he performed and what we could expect from him in the upcoming season.
In the table shown above, you can see his career majors statistics since he debuted with the San Diego Padres in 2012. After two promising seasons in California, where he pitched only slightly less than 25 innings per year, Boxberger managed to keep a very-low ERA an decent strikeout rates, even though he pitched 55% of the time in the pitcher-friendly Petco Park.
The most interesting part here is of course his year with the Tampa Bay Rays. Not only because it directly concerns our team, but also because it was his first full year, on a reliever scale. In 2014, Boxberger posted excellent metrics in every account, except maybe for his HR/FB ratio, although this can be affected by bad luck. Thus I will preferably concentrate on his strikeouts, walks, adjusted ERA and FIP.
ERA- and FIP- both try to assert a pitcher performance with taking in account the player's "home park" and compare it to the league average. Therefore, as the average is always 100, you can tell if a pitcher performed better or worse than the league by looking at these statistics. Everything below 100 is considered as better than the average and everything over as worse, hence the minus sign.
The table 2 tells us that the Padres Boxberger was somehow worse than the league average in terms of Field Independent Pitching, whilst his season with the Rays was the complete opposite. Indeed, a FIP- between 70 and 80 is considered as "excellent" according to Fangraphs standards. Added to the 14.47 strikeouts and 2.78 walks per nine innings, we can easily say that Brad Boxberger had an excellent year in Florida. But how good was it, compared to the other best relievers in 2014?
The Table 3 shows the top 10 relievers of last season, according to strikeouts per nine innings. Among this top 10, we can see that Boxberger had the league third best K/9 ratio in his category. Very good indeed. Nonetheless, his home run per fly ball ratio stands out a lot as being very poor, especially compared to other non-closers of this top 10 such as Wade Davis, Andrew Miller, Dellin Betances or Brett Cecil. His HR/FB surely explains his high FIP- of 79, which even if it is "excellent" still compares poorly to other relievers in the likes of Chapman, Miller or Craig Kimbrel. Furthermore, his walks per nine innings is the fourth best in this list, thus his FIP- could have been a lot better if not for the home runs. Actually, among every qualified relievers in 2014 according to Fangraphs, Boxberger had the second worst HR/FB ratio, behind only Francisco Rodriguez.
The thing with relievers is that you don't need to put an excessive focus on batted ball data. Why? Because it takes a lot of time for this data to "stabilize" and become meaningful. Ben Lindbergh participated to "Extra Innings", a Baseball Prospectus book published in 2012, in which he attempted to explain "Why Is a Building a Bullpen the Hardest Task a General Manager Can Undertake?"; a fascinating read that I can only recommend. In his chapter, Lindbergh presented a table showing how many seasons or plate appearances a certain stat needed to become relevant. Strikeouts or unintentional walks requires 126 and 303 PA respectively while HR/FB requires 1239 and BABIP 3729. Boxberger faced only 247 batters in 2014, so that's why HR/FB cannot be considered really seriously for him and for relievers in general.
Considering what I said before, I believe that Boxberger, if he maintains his good strikeout and walk ratios, will probably have a "luckier" year in 2015, meaning that his home run per fly balls number will significantly drop. Although, if it does not, it might be interesting to take a further look in his performances and try to explain why.
Other than that, you can still appreciate his top-notch balance mechanic as Doug Thorburn stated earlier this year in his Raising Aces column. Or you can also hope to see another "immaculate inning" (9 pitches 9 strikes 3 outs), as he achieved one last season against the Orioles.
Moreover, you might want to look at Boxberger fastball and changeup velocity differential in 2015. These two pitches constitutes his main arsenal and strikeouts ratios suggest that he uses it very well. With an average fastball velocity of 93.1 mph in 2014, Boxberger does not exactly qualify as a very hard thrower. However, he enjoys a 13.2 mph differential with his changeup, which is very good and well-above a league average of 9.8 according to Fangraphs. For reference, here's how Boxberger ranked in 2014 among other relievers in terms of fastball-changeup differential.
As you can see, he has the fourth-best differential, even though he throws harder than the top two relievers. It could be interesting to monitor his different velocities in the upcoming season and see if it helps him to achieve similar strikeout rates in 2015.
Now, in terms of projections, let's have a look at how ZiPS, Steamer and PECOTA projects Boxberger to be in 2015:
Each of the three projection predicts that Boxberger will be slightly worse in 2015 in terms of strikeouts or walks, although his win production could improve according to ZiPS or at least stabilize according to Steamer and PECOTA. These three systems are the ones I like the best generally, but feel free to make your own predictions for him in 2015 in the comments section!