BOSTON -- Shane Victorino looks at the Boston Red Sox's sub-.500 record and blames himself.

"If there's a bigger culprit for what has gone on up to this point, I'm at the top of the list by not being out there," Victorino said. "But looking at what's gone on, I have every bit of confidence in the guys in the clubhouse to keep continuing doing what they're doing."

Victorino, who won a Gold Glove in right field last season, has been limited to only 21 games this year because of a pair of right hamstring strains. He was slated to rejoin the team last week, but a slipped disk in his lower back derailed his rehab assignment.

The Red Sox don't have a timetable for when he might be ready to play.

Looking back, Victorino traces his problems to offseason surgery to release a nerve in his right thumb. The procedure, which he described to the Boston Herald as "exploratory," wasn't imperative, but given the fact that he had dealt with a thumb injury during the playoffs, it was recommended by Dr. Thomas Graham, a renowned expert at the Cleveland Clinic.

According to Victorino, the surgery prevented him from doing his usual offseason training program, which includes concentrated work in the weight room. He admitted Monday that he reported to spring training out of shape, prompting the Red Sox to put him on a program designed to strengthen his core.

"Trust me, man, I sit there and I talk about it and I think about it all day long," Victorino said Monday before the Red Sox's 2-0 loss to the Chicago Cubs. "What if I didn't have the (thumb) surgery, if I didn't have that two-month period where I couldn't do things in regards to training, to keeping myself in shape or getting myself into baseball-ready shape? But if I sit here and think about those things, then I'm going to drive myself even crazier than I already am. It sucks."