Focusing on depth for Patriots

The Cowboys are staring down the prospect of playing without their best defensive player this season after linebacker Sean Lee suffered what appears to be a torn ACL during the team's first OTA.

Dallas struggled defensively in 2013 due in part to a lack of depth across the board, and with Lee set to sit, the team is stretched thin at linebacker.

Injuries are an unfortunate -- and unpredictable -- reality in the NFL, and the news on Lee got us thinking about the need for organizational depth across the roster.

With that in mind, three positions strike us as areas where the Patriots are particularly thin, and where they will need either late free-agent additions or player development to ensure layers of depth.

Tight end: We thought the Patriots would assuredly draft a tight end this year, perhaps even in the top two rounds. That proved not to be the case, as the Patriots opted to instead sign two undrafted free agents, a reflection of how they viewed this year's prospect class. With Rob Gronkowski on the mend, Michael Hoomanawanui and D.J. Williams are the veterans leading the way right now. Hoomanawanui is best suited as a third tight end, while the duo of Justin Jones and Asa Watson are unknown commodities at this time. Dustin Keller, who has previously visited the Patriots, could still be on the radar as a post-June 1 signing.

Linebacker: If Jerod Mayo returns to 100 percent and Jamie Collins continues on his arc of development, the Patriots' starting trio is all set (Dont'a Hightower included). Moreover, Collins could be the type of linebacker -- like Mayo -- that can play 90 percent of the defensive snaps given his coverage skills. But that's asking a lot of a second-year player and injuries can quickly change any equation. The Patriots do not have a veteran reserve who has an extensive track record as a defensive linebacker, though Josh Hull and Chris White have been solid special-teamers. Bill Belichick is revered for his linebacker tutelage, and the Patriots will need some youngsters to quickly develop. In a pinch, Rob Ninkovich can also play strongside linebacker.

Safety: Count us among the Duron Harmon believers, as the second-year Rutgers product was really dependable, is respected within the organization for his smarts and approach, and has good physical tools. He could well be tasked with lining up next to Devin McCourty, though there have been rumblings about Logan Ryan trying his hand at safety, too. Either way, the Patriots don't have a glut of reserve safety experience on the roster, as even adding Patrick Chung didn't solve the issue (based on previous seasons, we'd hesitate to rely on Chung as more than a special-teamer). Perhaps Jemea Thomas, a sixth-rounder out of Georgia Tech, can assert himself into the defensive rotation with good positional versatility.