The Sports Xchange

FOXBOROUGH, Mass. — The biggest issues facing the defending champion New England Patriots heading into 2015 can be boiled down to the two key aspects of the passing game in a passing league: Who will throw the ball to open the team’s title defense and who the heck is going to keep other teams from throwing it all over the field?

Quarterback Tom Brady’s uncertain availability heading into the new season is something that head coach Bill Belichick and his team have really never had to deal with. Aside from returning after a 2008 torn ACL that cost him all but a single quarter of action that season, Brady has been the unquestioned, unchallenged and reliable-as-a-Maytag leader of the Patriots’ passing attack.

But Brady’s four-game suspension in the wake of the Deflategate scandal and as yet unresolved appeal that was heard by commissioner Roger Goodell on June 23 has left the quarterback spot for training camp practices, preseason reps and potentially the first month of regular-season action a bit unclear.

Brady could miss four games, no games, anything in between or take his appeal to the courts and keep the issues unresolved for an unknown period of time.

That means Belichick may not only have to prepare second-year backup Jimmy Garoppolo to start the Thursday night opener against the Pittsburgh Steelers, but also keep veteran Matt Flynn ready to go while also giving Brady all the reps he needs to assume his usual spot atop the depth chart at whatever point he’s allowed to do so.

The good news for Belichick and the team’s fans is that when Brady does take over the offense it appears to have all the makings of another Rob Gronkowski, Julian Edelman aerial show.

Things aren’t nearly so certain nor so optimistic in the back end of the New England pass defense in the post-Darrelle Revis era in Foxborough. Revis and Brandon Browner, who also is gone after just a single season at Gillette Stadium, helped transform the pass defense into a complementary factor in the team’s championship run a year ago. Now, though, what remains is a cast of unproven, unknown or reclamation projects.

Super Bowl hero Malcolm Butler will be given the chance to take over Revis’ left corner role after starting just a single game as an undrafted rookie last fall. Third-year developing player Logan Ryan could win a starting job on the right side. Free agent Robert McClain could replace departed veteran Kyle Arrington in the slot. Veteran signing Bradley Fletcher will have the opportunity to rebuild his career after a dismal year in Philadelphia.

The only thing that’s assured in the back end is that fresh off a new nearly $50 million contract, captain Devin McCourty will be expected to carry more of the load both as an experienced leader and a playmaker, something that he certainly was not asked to do in 2014 working behind Revis and Browner.

The NFL is a passing league. The Patriots are a passing team on offense and a team that’s struggled to stop the pass over the years save for last fall’s one-year rentals of Revis and Browner.

The passing game will be in the spotlight of bright sunshine this summer on the practice fields behind Gillette Stadium as questions abound not just about a pass defense that’s used to such focus, but also a Brady-led (maybe) passing game that’s going to once again carry the team as far as it goes this fall and winter.

CAMP CALENDAR

July 22: Rookies reported

July 29: Veterans report

July 30: First practice

Aug. 19-20: Joint practices in West Virginia with New Orleans

Aug. 15 (tentative): Camp ends

–Team strength: Tight end.

Rob Gronkowski openly talked about making quarterback Tom Brady look like himself again as of Week 5’s win over the Bengals last fall. The All-Pro tight end is indeed the key that puts Brady and the offense over the top. Gronkowski had a fully healthy offseason for the first time in years and was easily the most impressive and energetic player on the field throughout spring practice. Now, the addition of former Bills tight end Scott Chandler adds even more potential to the position. Chandler is a huge (6-foot-7) target that the Patriots clearly appear poised to use in tandem with Gronkowski not just in the red zone, but all over the field. The duo should give defensive coordinators and opposing players headaches, especially working with Brady and the rest of the impressive New England aerial attack.

–Breakout player: Linebacker Jamie Collins.

As impressive as Collins was in his second season last fall — leading New England with 109 tackles while adding four sacks, two interceptions, four forced fumbles and a pair of fumble recoveries — the versatile, athletic linebacker still has plenty of room to grow as he gets more experience. Collins is the modern mold for a linebacker with the ability to rush the passer, play the run and cover down the field. There is no question that an ascension to the Pro Bowl or even All-Pro status could be in the cards for the former second-round pick and budding New England defensive star.

–Work in progress: Secondary.

Devin McCourty will start at safety. The other safety spot and two or three starting cornerback jobs are total unknowns. The turnover in the back end could easily be forecast as the fatal flaw in the 2015 Patriots. A lot may be expected of surprise Super Bowl hero Malcolm Butler and many other unknown, unproven defensive backs.

McCourty is fresh off a new contract for nearly $50 million. That will bring huge expectations and, with Darrelle Revis gone, those expectations will be more difficult to fulfill.

The Patriots return the core of a high-powered passing attack. They may need it, as scoring a lot of points may be required given the unknowns and low expectations for the defensive backfield. Maybe Butler, Logan Ryan and free-agent addition Bradley Fletcher will work their way into a solid unit and be a pleasant surprise in the back end. Maybe.