TRENTON — In Thunder reliever J.B. Cox’s words, there have been a lot of low points over the past few years.

Starting in 2007, when he underwent Tommy John surgery, a career that at its outset looked promising has slowly but surely found its way into the doldrums.

The most recent valley, Cox says, came during his final two outings of 2009, during a series in Akron as a member of the Thunder.

In a span of an inning spread over two nights, Cox — a former closer at the University of Texas on whom the Yankees spent their second-round pick in 2005 — allowed four runs on four hits and four walks. Both outings directly led to a loss.

Almost immediately after that disastrous stretch, Cox decided it was time for a change.

“I’d already made up my mind that (baseball) wasn’t for me,” Cox said on Thursday at Waterfront Park. “I thought I was done completely. Obviously things have turned around since then.”

Before things could get better, however, he had to get away from the game for a time.

He enrolled youth and community studies courses at Texas in the hopes of finishing his degree and beginning a new life as a physical therapist.

He scored well in those classes, earning GPAs of 3.75 and 3.5 over two semesters before this baseball season began.

Sometime between now and then, however, as it so often does to players who have tried to divorce themselves from the sport, that familiar itch resurfaced.

Justin Vaclavik, a former member of the Altoona Curve and friend of Cox’s, was in the later stages of recovery from Tommy John and needed to play catch.

Unburdened from the pressures of the profession for the first time in years, Cox obliged.

“It was the first time I’d played catch in years where I didn’t have to think,” Cox said. “I didn’t care what the ball did. I didn’t care what anybody thought. Nobody was watching me. It was the first time I just got back to where I didn’t think.”

The scenario parallels nicely with that of another Thunder pitcher who had his competitive spark re-lit by a friendly game of catch.

Paul Bush, another Tommy John veteran, was on the track toward retirement before someone back home wanted a pro’s eye view of his own skills.

“I had a kid in my hometown who wanted me to play catch with him to see if I thought he had what it took to play professionally,” Bush said last year. “Once I started playing catch with him, my arm felt a lot better. As I started to up the volume, I came back stronger and it wasn’t hurting me, so I decided to give it another try.”

After his catch session with Vaclavik, things started coming together again for Cox.

“I got to thinking, when I finish this semester, I might as well start playing catch again.”

Under the watch of Longhorns pitching coach Skip Johnson, Cox started throwing again, and before long, he was on the phone with Mark Newman, the Yankees VP of Player of Development, asking for re-entry into the organization.

Once his second semester at Texas finished, Cox officially returned to the fold.

He debuted with High-A Tampa on June 15, and put up an 8.59 ERA in five appearances before being promoted Trenton earlier this week.

Thursday, in his first appearance with the Thunder this season, Cox threw two innings and earned his first professional win since August 14, 2008.

It’s been a long, strange ride for the man who was once considered a possible heir to Rivera. In the end, though, Cox says he’s a better man for the journey.

“I think it kind of made me a better person,” Cox said. “It’s one of those deals where I know it’s kind of cliche to say, but I went through it and I think I came out of it. I’m in a lot better place now than I was, definitely last year and previous years before that. Overall it was tough, and I don’t want to do it again, but it was kind of worth it in a sense.”

TRENTON — After putting together a nearly unblemished first half, David Phelps has been promoted to Triple-A Scranton/Wilkes-Barre. The move, although it hasn’t been officially announced by the team, was confirmed by multiple sources before the Thunder’s game with the Harrisburg Senators.

The right-hander, who was not in the ballpark yesterday, was 6-0 with a league-best 2.04 ERA and 84 strikeouts over 88 1/3 innings before the move up.

“Let’s face it, David did a heck of a job. He’s a pretty polished pitcher at this level.” manager Tony Franklin said before the game. “He proved that, and proved it with consistent outings. For half the season, you could always depend on him. That’s what we’re losing.”

With the move, the Thunder are left with one pitcher, D.J. Mitchell, remaining from the rotation to start the season. Jeremy Bleich is out for the season after surgery to repair a torn left labrum, Christian Garcia underwent his second Tommy John surgery and was released, and Ryan Pope has been shifted to the bullpen.

Phelps will start tonight for Scranton, who are in the middle of a series in Pawtucket. He takes the place of Dustin Moseley, who is being called up to avoid him triggering an out clause in his contract.

To open a spot on the major league roster, a reliever, believed to be either Chad Gaudin or Chan Ho Park, is likely to be designated for assignment.

Phelps’ departure also opens a spot on the Eastern League Eastern Division All-Star team. The Thunder have asked the league to fill that slot with Mitchell, who is 6-3 with a 4.70 ERA through 14 starts.

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After an awful outing during their last home game, the Thunder have placed closer Grant Duff on the 7-Day Disabled List with right elbow inflammation. Although the team does not like to place designations on pitchers’ roles, it is likely Tim Norton will slide in to the back-end role.

Duff stressed that he believes the injury is minor and should not cost him serious time.

Taking his roster spot is right-hander J.B. Cox, the Yankees’ second-round choice from 2005. He racked up an 8.59 ERA in five games with High-A Tampa before getting the promotion.

Cox is working his way back after taking a nearly year-long leave absence to ponder his future in baseball. His last game action in 2009 was June 25 with Trenton, the second of back-to-back poor outings in against the Akron Aeros.

During those appearances, Cox allowed four earned runs on four hits and four walks in a combined inning of work.

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Because Franklin is heading to the XM Futures Game, which will be held at Angel Stadium on July 11, an interim manager will be needed for the team’s last two first-half games, to be played at Prince George’s Stadium against the Baysox on July 11 and 12.

Jody Reed, who performed the same task last year for Franklin, will fill his shoes again.