FORT MYERS, Fla. — Now we know what Bobby Valentine meant when he said Bobby Jenks had a “terrible offseason” when asked about his plans for the reliever this spring.

Standing in his locker in the Red Sox clubhouse Thursday morning, the right-handed reliever detailed his offseason back surgery that he said resulted in a life-threatening spinal condition. Jenks had surgery on Dec. 12 at Mass General in Boston after recovering from a pulmonary embolism in his lung.

“With the whole blood clot issue last year, I couldn’t have the surgery until December,” Jenks said. “All the way up until that point, I was basically doing nothing but cardio and trying to get myself as strong as possible going into the surgery. I had the surgery on the 12th of December. It didn’t go that great. I had to have an emergency surgery on the 30th to correct what happened in the prior surgery. [Doctors] went in and had that fixed and [I have] been pretty much laid up the last two months.”

The Red Sox placed Jenks on the 60-day disabled list earlier this week and he said there’s no timetable for when he might be able to pick up a baseball and start throwing again. Jenks lost significant weight in the last six harrowing months before reporting to camp this week. Jenks signed a two-year, $12 million contract before the 2011 season. He appeared in just 19 games last season, with a 2-2 record and a 6.32 ERA.

Red Sox general manager Ben Cherington said the team continues to support Jenks through his rehab.

“He had a difficult year and a difficult offseason. He’s frustrated by where he is physically and he is making progress. He’s made progress in even the last few weeks and we’re going to do whatever we can to help him get back to pitching and we remain hopeful he can help us this year but it was a difficult ordeal for him last season and over the offseason.”

The initial surgery was performed at MGH by Dr. Kirkham Wood, chief of the orthopedic spine service at the hospital. The follow-up procedure was performed by Dr. Christopher Yeung in Scottsdale, Ariz.

“I don’t know whose fault it was but there was an error done inside,” Jenks said. “When I went in [for consultation], we had talked about it. I had four bone spurs basically on my spine. We talked about having the top two out and the third one was started and not finished. Basically, there was a serrated edge that sliced me open in two different spots and I was leaking spinal fluid. It just pulled at the bottom of my incision and just kind of blew up on me which caused an infection to climb up that incision wound, so now I had an infection in my spine.”

[Click here to listen to Bobby Jenks detail his harrowing winter of medical problems.]

Valentine said on Monday he’s not worried right now about Jenks in the team’s pitching plans to start the season.

“Bobby said he’d like to take it one week at a time. I’d say that means he’s a long ways away from thinking about baseball activities,” Valentine said. “He’s really had a terrible offseason health-wise so he’s a real backburner guy. I don’t expect to see him in many baseball activities for a while, if at all this spring.”

Indeed, while Jenks is with the team this spring, he hasn’t even been able to pick up and throw a baseball as he recovers from his ordeal.

“I haven’t touched a baseball since last year,” he said. “Prior to December, that whole timespan, we were just trying to strength everything going into the surgery instead of breaking anything down with throwing.

“I don’t know right now. With everything going on right now, I’m just trying to stay focused on one day at a time. I can’t focus on that now because I’m going to be here until June anyway so that’s just going to kill me mentally. So, I have to stay strong and positive right now.”

Jenks lost considerable weight after his pulmonary embolism and then kept the weight off to prepare for his first back surgery. How much?

“A lot, enough,” Jenks said. “I lost all the weight going into the surgery, with the thinking of coming out of the surgery as strong as possible.”

Jenks said the surgery was in the middle part of his back, in the thoracic region.

“It was a combination of everything that could’ve gone wrong, went wrong,” Jenks said. “If I didn’t have it done immediately, the infection could’ve gotten into my spinal fluid and up to my brain, and who knows what happens then. I could obviously not be here right now.”

He had a follow up emergency surgery on Dec. 30 in Arizona after complaining of serious migraine headaches. Jenks said he will let his representatives and lawyers determine whether to pursue legal action.

“That’s why I have people,” Jenks said. “I let them worry about that. If there’s something there, let them take care of it. My job is to get better and that’s what I’m going to focus on right now.”

The Red Sox made wholesale changes in their medical and training staff after the season but Cherington indicated that Jenks medical issues, including the embolism and surgery in December had no impact on the moves.

“The changes we made in the medical staff were obviously in motion well before his surgery in December and subsequent surgery,” Cherington said. “They weren’t related to each other.”