Third in an occasional series

looking at the Patriots

position by position.

The lasting impression of the 2015 Patriots offensive line will be the unit’s dismal performance in the AFC Championship game — a game in which quarterback Tom Brady was under siege from the get-go and hit 20 times.

The group struggled as a whole and individually throughout an injury-riddled season (no one was spared) and, in the end, it cost offensive line coach Dave DeGug­lielmo his job.

The return of longtime assistant Dante Scarnecchia won’t be the only change when it comes to this unit, but it could be the most significant move.

Scarnecchia has an excellent track record molding younger players, and the Patriots have three interior players coming off rookie campaigns — guards Tre’ Jackson and Shaq Mason and center David Andrews — who should continue to improve under his tutelage.

Center is a stable spot. Bryan Stork’s rugged play and surly disposition are perfect for the position. He got off to a slow start and struggled at times after returning from the short-term injured reserve list. His versatility proved invaluable as he was forced to play some guard and tackle because of injuries, but make no mistake, he’s at his best at center.

Andrews filled in admirably for Stork and will provide valuable depth. Both are signed through the 2017 season.

The guard position underwent a makeover due to the retirement of Dan Connolly and Ryan Wendell’s illness and injury. The veterans were missed. Wendell is a free agent, but a return would provide valuable experience, depth, and toughness.

Josh Kline was the team’s most consistent interior lineman (he received an in-season extension through 2017) but was clearly hurting late in the season as he dealt with a shoulder problem.

Jackson is better at pass protection but needs to be more physical in the run game. Mason is a road grader, but his pass pro needs work. The hope is that Scarnecchia can develop the sophomores (both are signed through 2018) into more well-rounded players.

Practice squad guard Chris Barker is signed through 2017.

Kelechi Osemele and Richie Incognito are the top guards on the free agent market, but neither would come cheap, and Incognito has a checkered past and may not be a great fit in the New England locker room.

Other names to keep in mind are Geoff Schwartz, Zane Beadles, Manny Ramirez (seriously), and Kraig Urbik.

From the draft, Stanford’s Joshua Garnett, Arizona State’s Christian Westerman, and Michigan’s Graham Glasgow are possibilities.

Depth and durability are the major question marks for the tackles. When healthy, the starters — Nate Solder on the left, Sebastian Vollmer on the right — provide solid protection and push.

But injuries are a reality, and when Solder went down in Week 5 with a torn biceps, it was the first (and worst) of what became a rash of injuries at this position.

Top backup Marcus Cannon injured his toe the following week, forcing Vollmer to switch sides, effectively taking away the team’s top tackle on both sides. Vollmer later suffered an ankle injury of his own and Cannon ran hot and (mostly) cold through the rest of the season.

The top three are all still under contract — Solder through 2017; Vollmer and Cannon through the upcoming season — as is Barker. Depth players Cameron Fleming (an exclusive rights player whom the team has reportedly tendered) and LaAdrian Waddle (restricted) are free agents. Fleming struggled to find consistency and Waddle played just one game because of a shoulder injury.

Solder, Vollmer, and, to a lesser extent, Cannon thrived under Scarnecchia’s guidance, so his return will help.

There’s plenty of tackle help available on the free agent market (Russell Okung, Jermon Bushrod, Mitchell Schwartz, Khalif Barnes, and Jake Long, among others) but it will be costly.

It’s a deep draft for tackles, with Mississippi’s Laremy Tunsil expected to be the first overall pick and Notre Dame’s Ronnie Stanley and Ohio State’s Taylor Decker also expected to go in the first round.

The Patriots could still land a quality plug-and-play tackle in the second round.

Names to remember are Michigan State’s Jack Conklin, Western Michigan’s Willie Beavers, Auburn’s Shon Coleman, and Texas A&M’s Germain Ifedi.

Jim McBride can be reached at james.mcbride@globe.com. Follow him on Twitter @GlobeJimMcBride.