Should Atlanta be concerned with Kimbrel pitching in the WBC? (US Presswire)

Both players and professional teams alike routinely balk at participation in the Classic, in spite of the gravity of playing for your country on an international stage. The primary reasoning behind the lack of star quality players performing in the WBC is the potential for injury, and the ramifications those potential injuries might have on a player's professional career.

Is there merit to this notion? Are the games and innings of the WBC that detrimental to the regular MLB season of a player?

I decided to take a look for myself, starting with pitchers from the WBC US entries of 2006 and 2009. For each WBC pitching staff, I looked at a handful of pertinent stats for each pitcher, comparing the year prior to the WBC, the year of the WBC, and the year after their WBC appearances to see if there were any significant changes in performance. With this, I also looked at injury histories of those years, again looking for drastic increases in games lost due to injuries, assuming the increased workload arising from WBC participation could lend a player to increased potential for injury.

Here's what I found, looking at all pitchers, for the 2006 and 2009 WBC staffs for the United States (pitching stats courtesy of Fangraphs, injury data courtesy of Baseball Prospectus, and their Player Cards):

I leave it to the reader to peruse the rosters of each of these WBC squads for further information - they can be found here and here. Briefly, the 2006 pitching staff had an average age of 30.4, with a range of 22 to 43. 2009 had an average pitcher age of 29.9, with a range of 24 to 36. The 2006 staff had 14 players, 10 of whom were relief pitchers; 2009 had a roster of 15 pitchers, 11 of those relievers. With respect to WBC innings pitched, the 2006 team threw 48 innings, with the 2009 squad clocking 67.2 innings in the Classic; individually, 2006 saw Roger Clemens leading the staff with 8.2 IP, with Roy Oswalt leading the 2009 staff with 11.1 IP. Overall, both the 2006 and 2009 WBC entries had most of their staff throw a smattering of innings, in the 2-5 IP range on average.

Overall, there is a trend towards decreased production the year of and following WBC participation for American pitchers, with the year after a WBC being the least productive and injury prone for a WBC pitcher. For the 2006 staff, a 12% decrease in innings pitched the year of the WBC, and a 20% drop the year following is seen. The 2009 staff has a similar dip, with 14% and 19% drops in innings pitched in WBC years, and the year after the WBC, respectively. Comparing the two WBC squads, there is a significant difference between the two with respect to games lost to injury, with the 2006 team appearing to be the more healthier across all years of interest. 2009 pitchers were decimated by injury before, during, and after the WBC, with the season ending shoulder injuries and surgeries of J.P. Howell and LaTroy Hawkin dominating the 2010 injury numbers. As a side note, the injury data I collected and used for this article only included games lost due to injury that could feasibly be due to performance-related wear and tear; therefore, games lost due to things like a stomach virus, or a finger contusion from trying to bare hand a come-backer, weren't included.

Speaking of relievers, let's break down these numbers a little further. Here are the same stats as the previous table, broken down by reliever and starter:

While we see the same trends, in general, as the previous table, it's obvious to see that relievers suffer the most when it comes to post-WBC MLB successes, both in terms of performance and injuries. Starters from both squads do a better job of avoiding the post-WBC injury bug, as compared to their relievers, but nonetheless, suffer a drop in innings and production. It is of interest to see how little the 2009 WBC pitching staff suffered with respect to Wins Above Replacement (WAR) over the years before, during, and after a WBC; 2009 starters actually had in some respects a bounce back year in 2010, with their 2010 average stats just as good, and in some instances, better than their pre-WBC numbers. In spite of hints of their usual, staid output, both WBC squads experienced significant reductions in MLB innings pitched and increases in games lost due to injury from the bullpen.

So what does this hold for the 2013 iteration of the WBC? While a small sample size still prevents us from making any rash predictions regarding the 2013 and 2014 MLB seasons for those selected for the WBC, there is enough happenstance to cast a weary eye towards the likes of Kansas City Royals reliever Tim Collins and Atlanta Braves closer Craig Kimbrel, and closely monitor their WBC and spring training performances. While it can be assumed that 2013 will be within their normal levels of productivity, how they are used in the WBC could play a role in their 2014 productivity and success, if WBC history lends itself to be true.

While the honour of playing for and representing your country on the international stage should never be downplayed, the numbers from the first two WBCs do lend merit to the balking of players and professional teams when it comes to participation in the WBC, on the grounds of future injury and performance issues. While the debate of when the ideal time of season the WBC should be played will continue long after the games of 2013 are over, for now, fans will have to be content with the rules in place when it comes to determining international bragging rights for who is the best baseball country.

As for relievers, beware of the World Baseball Classic.