Portland outfielder Brent Bryce homered against New Hampshire last week, and, figuratively, rounded the bases in isolation. Prediction: no other Sea Dogs position player will become an impact major leaguer.

The defending champion Fisher Cats may be having a down season, but the last-place Sea Dogs are even worse. Where have all the prospects gone?

A farm system that produced Jacoby Ellsbury, Jon Lester, Dustin Pedroia and other big-league All-Stars seems to have dried up. The Sea Dogs, since posting a winning record in 2008, have gone 213-257 (.453) over the past four seasons. Double-A baseball is a gathering place for the most talented and yet-to-be-jaded minor leaguers. The Red Sox, Blue Jays and other teams view Triple-A as a holding tank for veterans able to fill in at the major-league level. Double-A is for blossoming 25-year-olds on the verge of stardom.

So where are they?

Trades, bad luck and poor draft classes have contributed to the decline. Boston acquired Adrian Gonzalez by trading away prospects Casey Kelly, Anthony Rizzo and Reymond Fuentes. Both Casey (2008 draft) and Fuentes (‘09) were No. 1 picks by the Red Sox. Supplemental first-round picks Bryan Price (‘08) and Nick Hagadone (‘07) were dealt to Cleveland in the trade for Victor Martinez. (Boston also gave up Justin Masterson.)

Sometimes a prospect merely tantalizes the big-league club before fizzling out. Exhibit A: Stolmy Pimentel. The Red Sox signed Pimentel for only $25,000, and the Dominican fireballer was hyped as a can’t-miss power arm. He pitched in the 2010 Futures Game at Anaheim before completely bottoming out in the Eastern League, going 0-9 (9.12 ERA) with the Sea Dogs last season.

In 2008, the Red Sox drafted Rhode Island high schooler Ryan Westmoreland in the fifth round and paid the outfielder a $2 million signing bonus. Westmoreland, a five-tool player, shined for the Lowell Spinners in 2009 and was ranked among the top position players in the system. However, the youngster needed brain surgery after doctors discovered a congenital “cavernous malformation” on his brain stem. The 22-year-old has been working on a baseball comeback since surgery in March 2010.

Winning in the minors isn’t a barometer of what to expect down the road — but it’s an indicator. The Eastern League-champion 2005 Sea Dogs were led by Lester, Pedroia, Jonathan Papelbon, Hanley Ramirez and 13 others who eventually reached the majors. Things worked out for some of those guys in 2007.

While the Sea Dogs have struggled since 2009, the Fisher Cats have posted a 247-224 record (.524) and produced higher-quality pitchers. Since ‘09, Fisher Cats alumni Henderson Alvarez, Kyle Drabek, Drew Hutchison and Luis Perez have combined to win 20 games for the Blue Jays. For the Red Sox, Felix Doubront (six career wins) has been the only significant ex-Sea Dogs pitcher during the same stretch.

Ex-general manager Theo Epstein vowed to create a “player development machine,” and he fulfilled that promise for a decade, but he left slim pickings for successor Ben Cherington of Meriden, though Brentz and 6-foot-7 Sea Dogs right-hander Anthony Ranaudo are legitimate prospects. The Red Sox, who spent $11 million in signing bonuses on last year’s draft, will attempt to reload in the amateur draft June 4-6.

- - - - - - -

NECBL ALUMNI: Sea Dogs reliever Josh Fields, acquired in the Erik Bedard trade with the Mariners last season, pitched for the Keene Swamp Bats of the New England Collegiate Baseball League in 2005. It’s where he fell in love with the role of a closer.

“It was after my freshman year in college (at Georgia), and it was one of the most fun times I’ve ever had playing baseball,” said Fields, a first-round pick of the Mariners in 2008. “I asked them if I could close some games, and they gave me a shot. That jump-started everything. I finished out closing games in college and was drafted by the Mariners.”

In his junior year at Georgia, Fields led the NCAA with 18 saves while setting the school record. He was drafted 20th overall by the Mariners. College teammate Gordon Beckham, an infielder, was selected eighth overall by the White Sox.

Fields (0-1, 3.44 ERA) earned a save Wednesday night despite giving up a ninth-inning homer to Fisher Cats catcher Sean Ochinko. The right-hander has 26 strikeouts and seven walks.

“One thing I need to work on is consistency, being able to just pound the strike zone, I’ve been working on a lot of stuff this year, trying to just get my mental game a little bit better and work on some small mechanical stuff,” the Georgia native said. “I feel like it’s helping a lot, and I’m moving forward towards the major leagues.”

- - - - - - -

FISHER TRACKS: First baseman David Cooper, a career .299 hitter in the minors, was promoted from Triple-A Las Vegas to the Blue Jays and activated on Saturday. Cooper and fellow ex-Fisher Cat Yan Gomes are likely to share playing time at first base. Gomes made his big-league debut at third base. The Blue Jays also optioned ex-Fisher Cats reliever Evan Crawford to Triple-A.

- - - - - - -

FARM REPORT: White Sox farmhand Terry Doyle of Salem High worked a season-high eight innings for Triple-A Charlotte Knights in a 5-2 win at Durham last week. Doyle, who leads the team with 53 strikeouts, won his second straight outing, improving to 3-3 with a 3.46 ERA ... Jeff Locke from Kennett High of Conway spent three games in the Pirates bullpen before being returned to Triple-A Indianapolis last week. Locke was called up after Jason Grilli was placed on bereavement leave.

Yankees minor leaguers Jordan Cote of Sanbornton and Joey Maher of Bedford are pitching four or five live innings per week at extended spring training. The right-handers will continue to play extended spring games until rosters are assigned for the Gulf Coast League Yankees and the Staten Island Yankees of the New York-Penn League. Rosters will be finalized in mid-June. The daily routine consists of workouts and live games against farmhands from the Blue Jays, Phillies and Pirates. Cote, a Winnisquam of Tilton graduate, said he is pleased with his results and velocity thus far.

“It’s a lot of repetition. Every day is the same, but it’s still fun. I’m loving it,” said Cote, whose fastball has been topping out at 90-91-mph lately. “My velocity is gradually climbing. I’m pretty happy with how things are going. I haven’t given up a lot of runs.”

Staff writer Kevin Gray covers pro baseball for the New Hampshire Union Leader and New Hampshire Sunday News. His email address is kgray@unionleader.com.