"Yeah, at times, he was [tentative]," said manager John Farrell. "He's not running at 100 percent yet. The one thing that we're being cautious with here is that based on experience of having him come right back and play successive games -- and he's had a couple of those setbacks prior to going on the disabled list -- we want to be sure that there's a gradual improvement, which he's showing."
Originally, the Red Sox had hoped Victorino could go play a couple of Minor League games by the beginning of the week, but that now seems unlikely.
"To say that he's going to go on a rehab assignment tomorrow or the next day is probably a little more premature at this point," said Farrell. "We're just being, like you said, a little bit more overly cautious given what's transpired."
There hasn't been any setback for Victorino. The hamstring is simply healing slower than expected.
"There's been no setbacks, there's been no reaggravation of it," Farrell said. "It's just a matter of when he tries to get to that explosiveness, he doesn't have the quite the confidence and we're honestly telling him to more gradually get into it.
"What we don't want to do is turn this into an extended period where if it takes a couple of more days than the June 5 activation date, we're certainly willing to do whatever it takes to get by that. What we don't want to do is have that date be a drop-dead date where all of a sudden he's back and he re-aggravates things further."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.