Too much worry over 49ers' defensive line?

Our NFC West chat won't start til 1 p.m. ET, but one of the questions waiting in the queue caught my attention already.

"Let's face it, everyone is worried about the 49ers' defensive line," Andrew from Minnesota wrote. "I think, however, most people are overlooking the Ian Williams contract extension. We all gave puzzled looks at the Ray McDonald extension a few years ago, and that move paid off. Maybe Williams will be an awesome new anchor in the D-line? Thoughts?"

2012 49ers Defensive Linemen

Sando: The five-year extension McDonald signed before the 2011 season did come as a bit of a surprise, mostly for its timing and $20 million value. The 49ers had a new coaching staff, so it was tough to know from the outside which players the team might value most.

McDonald had played more than half the defensive snaps in two of the previous three seasons, however. He had played in 47 of the previous 48 games. McDonald was an established player and someone the team had valued as a third-round choice in 2007.

Williams, 23, was undrafted in 2011. He has played 39 snaps in four games over two seasons. His contract averages $1.5 million per year, less than half the $4 million average for McDonald. The deal for Williams included $2 million in guaranteed money, one-third what McDonald's contract contained.

I tend to think Glenn Dorsey's signing is the more significant one for the 49ers' defensive line. I'm not quite sure what the 49ers have in mind for him, but that signing indicates to me a specific plan is in place for the line in 2013.

As for the draft, I do think the 49ers need to address that position regardless.

McDonald and Justin Smith had both played at least 85 percent of the defensive snaps through Week 15, which was when an arm injury forced Smith to the sideline until the playoffs. Tampa Bay (three) and New Orleans (two) were the only other teams with more than one defensive lineman logging 85-plus percent of his team's snaps to that point in the season. The Bucs and Saints had a combined seven other defensive linemen logging at least 30 percent of the snaps to that point. The 49ers had none.

Tampa Bay and New Orleans ran different defensive schemes, of course. Outside linebacker Aldon Smith played on the line a fair amount for the 49ers depending on the situation. Still, it's a position the 49ers could stand to address. Smith is 33 years old and arguably the most important player on the defense. His contract runs through 2013 and the team will need to find a successor.