Continuing a season-long trend, The Thunder lost yet another member of their staff on Tuesday when right-hander Brett Marshall was placed on the disabled list.

Marshall, the ace on a team decimated by injuries, was 7-3 with a 2.99 ERA through his first 14 starts. Bursitis in his left leg means he joins fellow rotation-mates Josh Romanski (blister), Graham Stoneburner (groin strain), Craig Heyer (shoulder soreness) and Cory Arbiso (back stiffness) on the shelf.

The injury is not serious, Marshall says, and he doesn’t expect to be out long.  In fact, he took fielding practice and was in the weight room before the game. The Yankees typically like to control their starters’ innings by having them miss one start at some point in the season anyway, so Marshall missing just one start works out perfectly.

“I just started feeling it a little bit, but it’s nothing big,” he said before Tuesday’s game with Richmond. “They just want to shut me down for a start and then (I’ll) get back to it.”

Until now, the Thunder have patched their rotation’s holes better than they had any right to expect.

The trio of Adam Miller, Mikey O’Brien and lefty Vidal Nuno has posted a 2.61 ERA over 93 2/3 innings as members of the starting five.  That solid work not only helped keep Trenton afloat, but propelled it to the top of the standings.

“I think we’ve got guys who could be promoted, which allows us to cover some injuries. That’s a good thing.” manager Tony Franklin said before Tuesday’s game. “Probably the best thing about it is when guys do cover, they’re able to play more than one position. That versatility becomes very important.”

That malleability and good fortune has extended well beyond the pitching staff. For every player sent to the disabled list, the team has found a reliable replacement.

Luke Murton has clubbed 10 homers in Rob Lyerly’s absence. Kevin Mahoney provided offense, defense and late-inning magic while filling in at third base. Addison Maruszak started out shakily but has since played a solid shortstop while Walter Ibarra waits for his middle finger to recover.

Jose Pirela, who missed a month and a half with a concussion and was only expected to be used in a utility role anyway, has hit .381 with .440 and .546 on-base and slugging percentages while taking the injured Mahoney’s spot at third.

And who could forget Shane Brown, the team’s fifth outfielder, who has just 27 at-bats over 13 games but has already knocked two game-winning hits and earned a win on the mound.

“I think we’ve got a team full of versatile guys here who can play short, second, third, outfield, first base. That’s really helped us with all of these injuries,” Franklin said. “The biggest thing with all of these injuries is that we were able to cover them, which says that we do have a little bit of depth in the organization.”

Now they’ll have to count on Ricky Orta, a fourth-rounder of the Mariners in 2006 and who pitched most recently in the Rays organization, to keep things going. Orta was added to Trenton’s roster on Tuesday and will be used out of the bullpen.

A right-hander from the University of Miami, Orta missed all of 2010 with elbow surgery before being cut by Seattle. He latched on with the Rays before last season and made four starts with team’s affiliate in the Gulf Coast League.

NOTES: Romanski and Heyer each threw bullpens on Sunday and each will throw another on Wednesday. Heyer expects to be activated in early July. … Catcher Jeff Farnham said he sprained his ankle against Erie during the last homestand when he tripped on a sprinkler head. … Although there’s still no timetable for Cory Arbiso’s return, he says he has no pain in his injured back.