A run of aces in the NL

Roy Halladay

Think Halladay enjoys pitching in the National League? Maybe just a bit. After carving up the best offensive division in baseball (the AL East) for the past eight years, Philadelphia’s new ace is chewing up batters with numbing efficiency in 2010. Halladay has three complete games in six starts, including a three-hitter against the Mets on Saturday.

Cause for concern » It’s a minor one at best, but no one knows how Halladay will fare against the NL over the course of a full season. He’s also historically white-hot in May, June and July but mediocre (20-17 lifetime) in August.

Ubaldo Jimenez

This guy is the second coming of Ebby Calvin “Nuke” LaLoosh. Two years ago, Jimenez couldn’t hit water if he fell out of a [expletive] boat. The good news was NL hitters couldn’t touch him, either. Now? The walks are down, the strikeouts are up, and the Colorado flamethrower — after tossing a no-hitter in April — has the most wins in baseball.

Cause for concern » The guy’s stuff (100 mph fastball with movement) is ridiculous. And Jimenez’s career ERA is actually better at Coors Field. But ballparks at high altitude can’t be trusted and Jimenez has made only two starts at home this season.

Tim Lincecum

Seven years ago, advanced scouts throughout baseball were touting Mark Prior as the mechanically perfect pitcher. Then Prior, plus his flawless delivery and tree-trunk legs, took a permanent spot in the rotation for Team Disabled List. Meanwhile, Lincecum’s unconventional, elastic windup — long questioned by baseball experts — has paved the way to consecutive Cy Young awards. Take that, seamheads.

Cause for concern » Considering his lithe frame, arm trouble remains a concern. But that argument gets weaker with every lights-out performance.