Is Jenrry Mejia the Next Joba?

After a year in which three of their best players missed a major chunk of the season, the Mets needed some good news to kick off 2010. They’ve gotten some in the form of the performance of their best prospect, righthander Jenrry Mejia. After striking out more than a man per inning last season as the youngest player in the Eastern League (Double-A), the 20-year-old has been the talk of camp with his electric mid-90s fastball. He’s been so good, in fact, that the club is thinking of promoting him to the big leagues as a reliever. While he might thrive in that role, it would still be a bad decision.

Manager Jerry Manuel has pondered Mejia in the bullpen because he thinks he and Francsico Rodriguez will give the team a dynamic one-two combo to finish games. The problem is that Mejia still has a lot of development left. He admits his command issues, saying that he aims for the middle of the plate and hopes for the best. His slider also needs work, though he does feature an impressive changeup. As a reliever, these secondary pitches would not get the attention they need to improve.

The Mariners and Yankees should both provide cautionary tales for the Mets. Each tried to groom a young starter with ace potential, Brandon Morrow and Joba Chamberlain respectively, in the major league bullpen. While both performed well, they have also struggled in the transition back to the rotation. The Mariners ended up trading Morrow, while the Yankees have seemingly moved Chamberlain back to the bullpen once again.

What’s so bad about the bullpen? After all, both Morrow and Chamberlain have pitched well as relievers. Their teams, though, won’t realize maximum value. Starters affect a much greater portion of a team’s innings. If a team has 1450 IP in a season, a 200-inning starter covers 13.8 percent of the total time. A reliever who throws 70 innings affects just 4.8 percent of total innings. This shows up in Wins Above Replacement (WAR), too. Last year Barry Zito, who had had a 4.03 ERA in 192 innings, was worth 2.2 WAR, while Heath Bell, the NL saves leader, was worth 2.0 WAR. And if you don’t believe WAR, look at the free agent market, where the contracts given to top-flight starters typically dwarf those given to elite relievers.

The Mets might not have as strong a bullpen this year without Mejia, but by allowing him to properly develop in the minors they could see a greater return in the future. That’s not easy to stomach for fans who want to win today, nor is it an easy decision for Jerry Manuel and Omar Minaya whose jobs might be on the line, but it is the correct one for the future of the team. Considering the Mets haven’t featured a homegrown ace since Doc Gooden, you’d think they realize it would be foolish to stunt Mejia’s growth.