Portland Sea Dogs slugger Bobby Dalbec breaks his bat on an infield ground out during a May 7 game against New Hampshire. Dalbec, who leads the Eastern League with 20 home runs, was recently promoted to Triple-A despite a .234 batting average. Ben McCanna/Staff Photographer

When the Portland Sea Dogs resume play Tuesday at Hadlock Field, they will bring an overall .238 batting average with them.

Sound bad?

Well, yes, Portland ranks ninth in team batting average in the 12-team Eastern League. But that’s just one point below the league average.

No team is hitting this year. Erie, the league leader, is batting only .250. Richmond pulls up last at .220.

The Eastern League batting average is .239 – the worst in 48 years and a 14-point decline from last year. You must go back to 1971, when the league average was .234, to find a worse year. That was before the Eastern League adopted the designated hitter rule, so pitchers batted.  The Red Sox Double-A affiliate was in Pawtucket, which hit .229.

Other Double-A minor leagues also have experienced declines this year – the Texas League batting average is down 11 points, to .250, the Southern League is down five points to .241 – but nothing as bad as the Eastern League.

The factors are varied, from hitting approaches that emphasize power over average, to a lack of pure hitters and an influx of quality pitching prospects in the league.

“The pitchers are doing their job,” said former Sea Dogs pitcher Michael Tejera, now a pitching coach for the Harrisburg Senators.

Tejera gave a smile with his analysis. You’d expect a pitching coach to be prejudiced. But he has a point.

“I’ve noticed it,” said Harrisburg manager Matt LeCroy, in his sixth season. “There has been some really, really strong pitching, with plus-fastballs and good off-speed.”

LeCroy pointed to top prospects like the Yankees’ Deivi Garcia (87 strikeouts in 53 2/3 innings for Trenton) and the Mets’ Anthony Kay (1.49 ERA for Binghamton), who have since been promoted to Triple-A.

The Eastern League ERA is 3.58, down by almost half an earned run from 4.01 last year. (The 1971 ERA was 3.04.) Eastern League pitchers this year have a 1.26 WHIP (walks/hits per inning), which is even lower than the 1.28 WHIP of 1971.

While the league has pitching prospects this year, there are fewer touted batters.

Erie catcher Jake Rogers was batting .302 in 28 games before being promoted. He reached the majors this season.

Red Sox shortstop prospect C.J. Chatham leads the Eastern League with a .297 average. Ben McCanna/Staff Photographer

Red Sox shortstop prospect C.J. Chatham leads the Eastern League with a .297 average, but he was not considered Boston’s top offensive prospect. Corner infielder Bobby Dalbec was recently promoted to Triple-A Pawtucket, even though he was batting only .234.

Dalbec also hit 20 home runs, which led the league, as did his 68 walks. That latter statistic was a source of pride. Dalbec was baffled that anyone was concerned when he was batting only .190 early in the season, because he was still getting on base.

“All (critics) focus on (is batting average),” Dalbec said earlier this season. “Whatever my on-base percentage was – while I’m hitting .190 – if that’s an ugly start, that’s a pretty good ugly start.”

Dalbec left Portland with a .371 on-base percentage. That, combined with a .454 slugging percentage, gave him an .825 OPS, fourth-best in the league.

Dalbec also struck out 110 times, part of Portland’s 1,028 K’s, second-highest in the league.

“Swings are getting longer,” Sea Dogs hitting coach Lee May Jr. said. “There’s not as much emphasis on being a contact hitter.”

Long-time baseball followers may remember the adage for hitters with two strikes to “choke up on the bat, and swing at anything close.”

No more.

“All of that has fallen by the wayside,” LeCroy said. “With a combination of the way people are trying to hit the baseball now, and strikeouts – that leads to a lower batting average.

“You don’t see players grinding out long at-bats. Usually quick. Trying to lift the baseball.”

Eastern League teams are striking out 8.3 times a game, up slightly from 7.9 last year. But even when contact is made, there are fewer hits.

Coaches say factors like defensive shifts and more advanced video scouting also work against the hitters.

“It’s a mixture of things,” May said. “Hard to put a finger on one.”

One argument is that seasons come in cycles, and this one features fewer pure hitters. The Eastern League rebounded from its .234 batting average in 1971 to hit .242 in 1972 and .254 by 1973.

Maybe the bats make a comeback in 2020?