Chicago Cubs manager Dale Sveum commented Monday that, despite early-season struggles, Carlos Marmol had his confidence as the team's closer. That attitude is well and good for a 2012 season that's long since lost, but as Chicago looks to the future, Marmol's tantalizing talent will likely have to be put aside in favor of a closer with a steadier hand.

Even when he's at his best, Marmol has always been his own worst enemy. His control is so undependable that even in his best season, he walked 4.2 batters per nine innings (and that was while posting a 2.68 ERA and making the All-Star Team in 2008).

Obviously, some of Marmol's control issues are physical: no pitcher can put the ball exactly where he wants it on every pitch. However, Marmol's history of alternating between streaks of accuracy and stretches of debilitating wildness (this year's 8.4 walks per nine innings, for example) suggests that there's a psychological component at work here as well.

For all the attention paid to the mental side of hitting, where failure is guaranteed to come more frequently than success, pitchers can psych themselves out too. In the worst cases (Rick Ankiel, the infamous Steve Blass), they never recover, losing the ability to throw strikes altogether.

Marmol hasn't shown any signs of veering into that dire territory, but the frequency with which he walks (or worse, hits) the first batter he faces suggests that pressure is not always his friend. That being the case, the Cubs should probably be happy with the few strong seasons they've already gotten out of Marmol in the bullpen and look for another closer for the long term.

The problem for Marmol, and the Cubs, is that when he blows up, it could be very sudden.

Consider erstwhile Mets All-Star Armando Benitez, another closer who—at his best—saw every at bat end with a walk or a strikeout. He went from a league-high 47 saves and a 1.29 ERA in 2004 to 19 saves and a 4.50 ERA in 2005 and never recovered his effectiveness.

Benitez's collapse happened at age 32, just a few years older than Marmol is now. Although Marmol's current streak of converting 13 consecutive save chances is an encouraging sign, there's just no way to be sure when the bottom is going to fall out.

If the Cubs don't start grooming a viable replacement closer, they may find themselves having no choice but to throw an unprepared setup man into the fire and hope for the best. That's a situation no team wants to endure.