I don't think Earl is really quite the same time frame as Hollings for several reasons.
First, Hollings was injured earlier in the season, after only 3-4 games. Earl was injured about a month later in the season, so he will probably take about a month longer to rehab. Hollings was actually way ahead of schedule and was able to practice at the beginning of training camp, although he was a little limited. I don't know if Earl is going to be ready to go at the beginning of camp.
More importantly, there is a little more depth at strong safety this year than there was at running back last year. There was a need to get Hollings on the field ASAP because no one knew if Mack was going to be the answer as a full-time starter, if Wells was going to step up as a second year player, or if Davis was going to be able to be more than a return man. There was a lot of uncertainty at RB last year, much more uncertainty than there is at strong safety this year. Brown has been a pretty solid starter the last two years and Walker has shown some potential at safety while being a strong special teams player.
I see the Texans being even more cautious with Earl this year than they were with Hollings last year. He may be on the injured list all year just so they don't have to make a roster decision about cutting either Brown or Walker, assuming Walker is fully recovered from his injury last year.