On April 9th last season, 21 year old Kelvin Herrera, who had just 12 games of expierence over three years in Low A and just 23 games total experience pitching in the United States, made his High A debut for the Wilmington Blue Rocks.  The results were typical Herrera:  two innings, one hit, no runs, one walk and four strikeouts.

There has seldom been any doubt about the young Dominican’s ability to get batters out.  In his American debut with the Rookie Burlington team, Kelvin had struck out 45 and walked just 5 in 50 innings of work.   That was enough to earn him a promotion to the Low A Midwest League at the tender age of 18.  In three appearances over 13 innings, Herrera was touched for just 3 runs.   Used mostly as a starter, hopes were high for Herrera.

Elbow trouble, however, limited Herrera to one appearance at Burlington in 2009 and shut him down again my mid-May in 2010.  Simply put, the Royals spent the better part of two seasons seeing far too little of Herrera’s upper 90s fastball, excellent changeup and solid curve.  To many, it seemed that Herrera would join the long list of promising young arms that could not hold together long enough to even get within spitting distance of the majors.

Fast forward (or reverse Jason Kendall) to that Wilmington debut.  It came, not as a starter as he had been in 18 of his career 23 appearances, but in relief.   With his fastball touching 100 working out of the pen, Kelvin made seven more appearances in Wilmington: allowing just one run (a solo homer), while striking out 12 and walking 2. 

That performance earned Herrera a promotion to AA, where he once more excelled.   Kelvin threw 36 innings over 23 appearances and struck out 40 batters.   He walked just six and allowed only 22 hits (4 of them home runs).    That earned Herrera another promotion, this time to AAA Omaha.  There, he struck out 18 in 17 innings, allowing just 12 hits.  The only mark against Herrera was a higher than previous walk rate as he issued 7 free passes in his time in AAA.   Still, outside of a messy three run, three walk performance on September 1st, Herrera was tagged for just one other earned run in the AAA regular season.

Herrera was tagged for two home runs in four innings of playoff work for Omaha, but he still earned his third promotion of the season to the majors in late September.    Tagged for another home run and three earned runs total in his major league debut, Herrera was given just one other major league appearance, throwing a 1-2-3 inning on September 26th.   Basically, we did not come close to seeing enough of Herrera at the major league level to have any idea what the soon to be 22 year old will be able to accomplish.

That said, Kelvin Herrera rocketed through four levels of organized baseball in one season; all while adapting to his new role of not just a relief pitcher, but as a closer.  Not only was Herrera pitching in high leverage situations in almost all of the 69 innings he threw last year, but doing so while being among the younger players at virtually every level. 

Still, as impressive as Herrera’s 2011 was, we are still talking about a player with just 220 innings of professional experience (that includes 43 in the Dominican Summer League) and one who spent the bulk of 2009 and 2010 with a bad elbow.   Will the elbow hold up?  Can Herrera be the dominant late inning reliever in the majors that he was at three levels in 2011? 

While it is not a sure thing, Herrera certainly seems to be more likely to be the next Greg Holland than the next Carlos Rosa.  Even with the addition of Jonathan Broxton, there is a very good chance that Herrera breaks camp with the Royals in early April.