Can the Padres’ starters keep this up?

Heading into the 2010 season, the San Diego Padres were expected to rank among the bottom tier of National League ball clubs. The most prominent question surrounding the Friars was not, “will they contend?” but rather “where’s Adrian Gonzalez headed?” Yet, improbably, the Padres sit atop the NL West standings with a 51-37 record. San Diego’s Pythagorean record is 53-35, as the team has outscored the competition by 72 runs.

Even adjusting for lumber-sapping tendencies of Petco Park and the Herculean feats of Gonzalez, the Padres’ offense as a whole hasn’t stood out — according to Fangraphs, San Diego places 13th in the NL in Park-Adjusted Batting Runs, at -14.1 runs below average. Rather, the club’s strong play has been predicated on excellent defense (the Padres lead the NL in Ultimate Zone Rating), a lights-out bullpen (first in xFIP) and a surprising starting rotation. Mat Latos is pitching like an ace, and Jon Garland, Wade LeBlanc and Clayton Richard are all exceeding expectations.

It’s those starters that I’m most concerned about. As a unit, Padres starters have the third-largest negative gap in the majors between their ERA and xFIP. San Diego starters have a sparkling 3.46 ERA, but a 4.18 xFIP that ranks eighth in the NL. It seems reasonable that the starters, backed by strong defenders, could post somewhat lower ERAs than their fielding independent marks would suggest. But slick leather does not fully explain the ERA/xFIP dichotomy.

Padres defenders have saved 36.2 runs more than the average club so far this season, or roughly 0.41 runs per nine innings the Padres have pitched. But San Diego starters have exceeded their xFIP marks by a collective 0.72 runs per nine innings. Several Padres starters have also benefited from a very high rate of stranding runners on base:

The MLB average for strand rate is roughly 70-72 percent. Pitchers do exert some control over their LOB rate — better pitchers will retire more hitters overall — but those with extreme strand rates tend to return toward that big league average. And some of these LOB rates are extreme. LeBlanc has the highest strand rate in the majors among qualified MLB starters. Latos ranks seventh, and Richard places 19th. Garland’s LOB rate is 4.1 percent above his career average. It’s not like LeBlanc turns into Superman when a runner gets on base — his xFIP in such situations in 4.96. Latos’ xFIP with men on is 4.07, Richard’s is 4.09 and Garland’s is 4.67.

I’m skeptical about San Diego’s rotation in the second half. Latos is exceptionally talented, a legitimate front-of-the-rotation arm. But he’s not going to keep a sub-2.50 ERA once his BABIP rises and his strand rate declines. There’s also concern regarding his workload — Latos is on pace to blow by his previous high in innings pitched. LeBlanc looks like a back-end arm in a neutral pitching environment who can pitch above that level in San Diego. Still, I seriously doubt he puts up something approaching a 3.30 ERA from here on out. Richard keeps the ball on the ground and has improved his control, but he’s probably headed for regression as well. Garland probably won’t leave as many ducks on the pond or be as fortunate on balls put in play. It hardly seems like a Correia rebound will offset all that.

Here are Oliver’s rest-of-season ERA projections for San Diego’s starters:

Latos: 3.06
Richard: 4.11
LeBlanc: 4.56
Garland: 4.59
Correia: 4.77

There’s a huge gap between Latos and everyone else, and he’s the guy who might be least available. Maybe the unit can best these marks with continued strong defensive play behind them. But, even if you think the team will keep on playing fantastic D, it’d take a lot of faith to expect the Padres’ starters to keep pitching so well.