Should Cardinals keep Rosenthal at closer?

From Derrick Goold of the St. Louis Post-Dispatch:

The Cardinals will open spring training in 2014 with [Trevor] Rosenthal as closer, manager Mike Matheny confirmed Monday during a season review news conference at Busch Stadium. ...

Rosenthal often expressed his interest in competing for a spot in the rotation for 2014, but the club has long believed his power fastball and mentality would eventually thrive at closer.

"Right now there is no reason to go anywhere differently than how we ended," Matheny said. "Trevor Rosenthal is a guy who is going in there getting the saves for us. That's how we're heading into this spring. ...

"This is a touchy topic in the fact that we know Trevor would like to start and be a starter someday. And we don't deny the fact that that could realistically happen and he would do a terrific job at it. ... When you look at our club and what we have ... we have need for that bullpen ... all based around our closer. We have a lot of confidence in how he has been able to handle that position."

The Cardinals are a smart organization. They know a good starting pitcher is more valuable than a great closer and that closers are easier to find than starting pitchers. But Matheny is right, the Cardinals do have depth in the starting rotation, which would line up something like this for 2014:

Adam Wainwright

Michael Wacha

Shelby Miller

Lance Lynn

Joe Kelly

Jaime Garcia (expected to be healthy for spring training)

Carlos Martinez

Tyler Lyons

That's eight quality options, before even getting to Rosenthal.

What's most interesting about the decision is that if Rosenthal hadn't fallen into the closer role almost by default -- Jason Motte got hurt in April and then Edward Mujica tired in September after superbly filling in for Motte -- it would be easier to give him a chance at starting. He was so dominant as a reliever, particularly in the postseason when he pitched 11.2 scoreless innings, that it now becomes more difficult to remove him from that role. He's Matheny's 100-mph security blanket. But if he was still in the less-valued role of setup guy the Cardinals would probably be more willing to start him.

When starting in the minors, the reports on Rosenthal were that he worked in the mid-90s while showing a hard curveball and solid changeup. In 2012, between 17 starts in Double-A and three in Triple-A, he posted a 2.97 ERA with 78 hits, 42 walks and 104 strikeouts in 109 innings. While pitching in relief in the majors, Rosenthal stuck almost exclusively with his fastball, which averaged 97.3 mph and reached 101. Including the playoffs, Rosenthal threw 1,461 pitches in 2013 -- 1,161 fastballs (80 percent). He threw 15 percent changeups and basically ditched the curveball.

As a starter, he would likely need all three pitches to succeed. The scouting reports on him were certainly positive in that regard, and you would have to think Rosenthal would have more upside as a starter than Lynn or Kelly (who will find it difficult to replicate his 2.69 ERA). Of course, we don't know for sure how Rosenthal would fare, while we do know how he did as a reliever; he has limited experience above Class A as starter and Lynn, while more of a mid-rotation workhorse, has at least proven he can handle 190-200 innings a season as a starter.

The problem with keeping Rosenthal as a closer is that you have to get the lead before he has any value. Rosenthal didn't do the Cardinals any good when he pitched the final innings of 3-1 and 6-1 losses to the Red Sox in Games 5 and 6 of the World Series. If Rosenthal has top-of-the-rotation potential, do you owe him that opportunity? After all, starting pitchers make a lot more money than relievers, and the kid wants to start. Is this the same debate as the Nationals sitting Stephen Strasburg in 2012 for (arguably) the good of his long-term future?

The other issue is what the Cardinals do with Martinez, who was rated a notch above Rosenthal as a starting pitching prospect entering 2013. He only pitched 79 innings in the minors in 2013, so do you send him back down for more seasoning as a starter, and insurance against an injury from another starter, or use him as a power arm in the eighth inning like you did in the postseason?

Hey, these are good problems to have and it's possible the Cardinals end up trading one of these pitchers to find an upgrade at shortstop. As good as Rosenthal was in the postseason, closers are easily replaced -- in fact, only two teams are likely to begin 2014 with the same closer it had in 2012. For me, I'm trying to extract the most value out of a player. I would try Rosenthal as a starter, move Kelly to a swingman/relief role and put Martinez in the pen for a year.