By Peter Abraham, Globe Staff

Jon Lester starts for the Red Sox tonight. There's good and bad to that. Let's break it down.

The good: He's Jon Lester. He's 15-9 with a 3.49 earned run average. He's an All-Star.

The bad: Lester has a severe case of the stinks lately, going 1-3 with a 6.97 ERA in his last four starts. He got rocked by the Yankees on Saturday, giving up eight runs on eight hits in 2.2 innings.

The good: He owns the Orioles. Lester is 14-0, 2.33 in 17 career starts against Baltimore, 7-0, 2.47 in nine starts at Camden Yards. It's the longest active win streak by any pitcher against any team and the longest ever against the Orioles.

The bad: Lester is pitching on three days' rest for only the second time in his career, the first time coming in 2008. He lasted only five innings that day against the Angels, giving up four runs on nine hits and two walks. He had one strikeout.

Given that the Red Sox treat their starters like delicate porcelain figurines, a change in the routine is a built-in excuse.

The good: Seriously, he owns the Orioles. Their current players are hitting a collective .233/.289/.307 against Lester. Plus he threw only 55 pitches in his last game, on Saturday against the Yankees. It's three days' but it's three days' rest after a short performance.

The bad: Red Sox starters are 3-12 with a 7.28 ERA in the last 23 games. They've fallen off a cliff as a group.

The good: Lester is 17-6 with a 3.43 ERA in 28 appearances in September or October in his career. He also has a 2.57 ERA in eight playoff games and this is basically a playoff game.

The prediction: 6.1 innings, 7 hits, 3 runs, 3 earned, 3 walks, 5 strikeouts