When John Lackey started Monday night against Toronto, the Red Sox had an ERA of 5.04, third-worst in the American League.

It is a startling number for a team labeled by many in March to have the best rotation in baseball.

That rotation’s ERA was even higher. At 5.11, it also was the third-worst in the league.

This season, Boston hitters have performed better than expected. The Red Sox had 165 runs before Monday night’s game, not far off the run production of division leaders Tampa Bay (174) and New York (178.)

Yet the Sox had been outscored by 12 runs this season, while the Rays (plus-80) and Yankees (plus-67) had far outscored opponents.

There are plenty of baseball people who think run differential is the easiest way to determine a club’s success in a season.

Score more runs than you give up and you’ll win more games than you lose. It has been the biggest difference between the Sox and their divisional competition this season.

Teams with good starters don’t usually fall into long losing streaks.

That’s why it was easy to think the Sox would be a playoff contender again in 2010. It’s also why it is way too early to give up on the team. Sunday night was an example of that fact.

Having lost the first two games with the Yankees by a combined score of 24-6, the Sox were in danger of being swept at home by one of the teams they were trying to catch. A loss Sunday night would’ve left Boston 81/2 games back of second-place New York.

Instead, Jon Lester calmed the fears of Red Sox Nation with a brilliant seven-inning performance.

He struck out seven while giving up just two runs on four hits. Lester is 42-12 with a 3.45 ERA in his career in games pitched after April. With April gone, there’s no reason to believe Lester will not pitch well every fifth day.

John Lackey was brought in this offseason to make a good Sox rotation better. He has pitched as advertised, with a 3-1 record and a 3.89 ERA going into Monday’s start. He’d had only one bad outing with the Sox before Monday’s outing, a start against Tampa Bay on Patriots Day in which he gave up eight earned runs in 31/3 innings.

Maybe Lackey’s just not a morning guy. Take that 11 a.m. start out of the equation, and Lackey was 3-0 with a 2.16 ERA before Monday night.

The toughest guy to figure out is Josh Beckett. Friday night, it looked as if he had the best stuff in the rotation. He began by striking out five of the first six batters, all on swinging strikes.

That was forgotten by the end of the sixth inning, and Beckett out of the game after allowing nine runs.

Something is wrong; Beckett’s too good a pitcher to have a 10.48 ERA over his last four starts. The Sox think so too and have pushed back his next start two days.

Behind the Big Three, Clay Buchholz has pitched well despite his loss to the Yankees on Saturday, and Daisuke Matsuzaka has been plagued by one bad inning in each of his two starts.

In his first start, five of the six earned runs came in the fifth inning; in his next, four of the five runs he gave up came in the first.

Can Matsuzaka overcome those bad innings to once again become the pitcher who went 18-3 with a 2.90 ERA just two years ago?

It’s an important question for the Sox as they try to string together a run before Memorial Day.

A much bigger question is what is wrong with Beckett. There’s a reason the Red Sox locked him up for another four years last month. He is an elite pitcher who has posted identical 7.22 ERAs in each of the past two Aprils. Last year, he won 15 of his 19 decisions after that month, never suffering more than one loss in a month from May through September.

This season, Lester has already shown you can get back on track midstream. He gave up 15 earned runs in 16 innings over his first three starts, but has an ERA of 0.90 in his last four. If Beckett can follow Lester’s lead, if he can turn it around like he did last season, this will be too good a rotation to fall completely out of the playoff race this early in the season.

 

Tom Caron is the studio host for Red Sox broadcasts on the New England Sports Network. His column appears in the Press Herald on Tuesdays.