Matt Maiocco is reporting that Justin Smith will undergo surgery on his partially torn triceps muscle later this week. The report indicates Smith suffered an approximately 50% tear, and will require three months of rehabilitation. That would get him back in time for the end of OTAs. I imagine he won't do a lot of physical work in OTAs, even if he is back to 100%, as the team would be plenty fine just getting him back for training camp in late July.
The 49ers defense struggled mightily after Smith's injury. It was important to get him back for the playoffs, but even still, that right side of the defensive front was struggling to make a regular impact in the playoffs. This alone proves just how valuable Justin Smith is to this defense.
The 49ers will need to consider their defensive line options heading into free agency and the draft. The team has Will Tukuafu and Demarcus Dobbs as potential defensive ends, but we don't know how the 49ers feel about either man as an option behind Smith. Dobbs was the team's leading special teams player in terms of snaps before he went down with his injury. He received some limited work at defensive end during the season, but has not been given a full run at the position outside of the preseason.