Cole Sturgeon played his 300th game for the Portland Sea Dogs this week. Heading into Wednesday night’s game in New Hampshire, Sturgeon is tearing up the Eastern League with a .369 average, 1.018 OPS, five home runs, 5 for 5 in stolen bases and perfect glove work in the outfield.

Yet, when the Sea Dogs return to Portland for a doubleheader on Thursday, Sturgeon is likely still to be in Double-A.

Earlier this year, Sturgeon referred to the “logjam” in Triple-A, understanding why he remained in Portland, for now.

Of the four outfielders in Triple-A, only one is batting above .215. But Rusney Castillo (.312/.710) is not going anywhere with his $11 million salary (which currently does not count against Boston for the luxury tax, as long as he remains off the 40-man roster).

As for the other three outfielders, all have reasons to be in Pawtucket.

Aneury Tavarez, 26, is batting .215 with one home run (23 strikeouts/five walks). Boston is waiting for him to regain his stroke that had him bat .336 in 2016 with the Sea Dogs. He came back to Portland last year, hit .377 in 18 games and went to Pawtucket, where injuries limited him to 33 games. The question is how long will Boston be patient?

Jeremy Barfield, 29, flexed his muscles last year, with 27 home runs in 92 games for Portland – a Sea Dogs record since they became a Red Sox affiliate (and Hadlock added the Maine Monster). This year, re-signed as a minor league free agent, Barfield is batting .129 with two home runs (33 strikeouts/10 walks).

Ramon Flores, 26, was acquired from Arizona in a cash deal. He has major league experience (119 games) and provides insurance for the Red Sox. But Flores is batting only .187 with two home runs (26 strikeouts/three walks).

Boston traded for Flores on March 25, which sunk Sturgeon’s chance for Triple-A. Sturgeon impressed in nine major league spring training games (7 for 12, .583 average with a home run and two doubles).

“It matters,” Sturgeon said of where he was placed. “But the ability to play every day matters as well.”

Sturgeon also knows the promotion to his ultimate goal – the major leagues – can come from Double-A or Triple-A.

“They’ve shown they will call up guys from here,” said Sturgeon, who watched infielder Tzu-Wei Lin jump from Portland to Boston last year.

For now, Sturgeon is showing all five tools.

He should be in Pawtucket and will be when the Red Sox make room for him.

The top pitching prospect for the Boston Red Sox, left-hander Jay Groome, will undergo Tommy John surgery next week, the team announced on Wednesday.

Groome, 19, was Boston’s first-round draft pick (12th overall) in 2016.

Coming out of high school, Groome pitched only 62/3 innings of rookie ball in 2016. Last year, he was sent to low Class A Greenville. But he was limited with injuries and made only 11 starts (6.70 ERA, with 58 strikeouts in 44 innings).

Groome was held back in extended spring training in Florida this year with what was called a mild forearm strain.

The surgery on his left elbow will take place May 15 in Los Angeles.

THE BINGHAMTON series features five games in four days – a 5 p.m. Thursday doubleheader includes a makeup game from an April 15 postponement.

Tim Tebow, the former NFL quarterback, returns with the Rumble Ponies. He’s batting .244 with three home runs.

TWO SEA DOGS will pitch for the first time at Hadlock this year – starter Travis Lakins and reliever Jordan Weems.

Lakins, 23, the No. 16 Red Sox prospect according to milb.com, is coming back from a stress fracture in his elbow he suffered last summer in Portland. He has made three starts – all limited to three innings – and has allowed no earned runs, eight hits and one walk, striking out 13. He is tentatively scheduled to start Sunday.

Weems, 25, used to be a prospect, as a catcher. He was Boston’s third-round draft pick in 2011 ($500,000 signing bonus) but struggled. After beginning the 2016 season in Portland, he returned to extended spring training in Florida to begin work as a reliever.

He began this year in Salem (0.68 ERA) and was called up to Portland on May 4.

Weems will become the second Sea Dogs catcher who later returned to Hadlock Field as a reliever. The other? (Answer below).

IN PAWTUCKET, lefty Jalen Beeks had an impressive outing on Wednesday, allowing one run and four hits over five innings, recording one walk and six strikeouts. His ERA is 1.72.

IN SALEM, third baseman Bobby Dalbec (fourth round, 2016) has five home runs and seven doubles … but only six singles. Dalbec, batting .176, has struck out 43 times in 30 games. Dalbec’s development was slowed last year by a broken hamate bone.

Another top infield prospect, C.J. Chatham (second round, 2016), was just promoted to Salem, after starting the season with a .307 average in Greenville.

LOOKING BACK: The first Sea Dogs catcher to convert to relief pitcher and return to Portland was Edgar Martinez (not related to the former Seattle DH). Martinez caught in 2004, and then pitched for the Sea Dogs in 2006. Martinez pitched the next two seasons in Pawtucket, and then in independent ball and the Mexican League until 2015.

Staff Writer Kevin Thomas can be reached at 791-6411 or:

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Twitter: @ClearTheBases