The St. Louis Cardinals need a closer. Heck, they need a reliable arm out of the bullpen. The Cardinals pitching rotation—save for maybe Lance Lynn—has been dominant. They hold a 2.19 ERA (3.08 FIP), hold an overall record of 8-3, induce a lot of ground ball outs and have over a 2-to-1 K/BB rate.
The bullpen is another story.
Their ERA is 6.08 (4.16 FIP), they've lost three games for the starting staff with just two saves in 40 innings pitched. Their two best pitchers are Randy Choate—he of just 2.1 innings pitched—and Edward Mujica who is posting a 1.80 ERA. Choate probably doesn't have the stuff that you'd want out of a closer—his walks are nearly four per nine innings, but Mujica just might. You could argue that Boggs deserves more chances or that Rosenthal deserves a chance, but do you really feel comfortable with either they way they are pitching right now?
Mujica has been a great acquisition for the Cardinals since coming over from the Miami Marlins in 2012. He's kept his ERA at or below 3.00 and consistently strikes out batters at a rate of just over 20% versus a just-below 5% walk rate. The problem is that Mujica has never closed on a consistent basis.
Boggs has got to straighten himself out at some point, right? And Rosenthal might start to figure himself out soon, right? Maybe but right now the Cardinals shouldn't be in a gambling mood. Yes, they are 8-6 in this young season but the rate that the bullpen is blowing games—and making some closer than they should—has got to disturb management.
The numbers do say to go to Mujica in the ninth. Yet the numbers also say he's going to calm down on his 9-to-1 K/BB rate and his .197 BABIP is practically unsustainable. He is leaving 100% of his runners on base, though and is only yeilding ground balls around one every three at bats. The most telling in all of this his that his FIP is close to three runs higher than his ERA. This all could point to an implosion in the future but it also says he's hot right now—keeping in mind he's thrown just five innings. He's also shown to be somewhat trustworthy as he's got four holds with no blown saves.
Mujica could—for the time being—put the bullpen on solid ground by allowing Boggs to return to his more dominant role in the 8th and allowing Rosenthal to be the seventh inning man. I personally believe that the Cardinals should be shopping for some 'pen help--especially with an asset like Matt Adams.
The Cardinals have the offensive firepower to win a lot of games and a rotation who can shut down the best lineups in baseball. They need to get this bullpen situation cleared up quickly or they may be looking back at April as the month they gave up too much ground in pursuit of late fall baseball.