It’s hard to launch a new series in the face of Olympics ratings domination, but try launching a whole new football season. A preseason NFL tradition since 2001, “Hard Knocks” (9 p.m., HBO) returns to cover the training camp of the Miami Dolphins. Although this affords Dolphins fans and others an inside look at their team’s preparations and roster cuts, television expose has not always been a blessing for sports franchises.

The Dolphins don’t have to go far to ask Miami Marlins fans if the decision for the baseball team (most notably, manager Ozzie Guillen) to appear on the Showtime series “The Franchise” has been fruitful. Chosen by many preseason prognosticators to dominate their National League division, the Marlins have been a bitter disappointment.

Like many reality shows, “Hard Knocks” has to emphasize “drama,” and that may not be entirely good for the team. Due to a labor dispute, there was no “Hard Knocks” last summer. In 2010, “Hard Knocks” offered New York Jets coach Rex Ryan plenty of chances to make wild statements and predictions and put himself forward as either a leader or a distraction, depending on your point of view. After his team’s disappointing 2011 season, Ryan promised to be more buttoned-up. Such behavior could work out better for his team, but it would make him a dull presence on “Hard Knocks.”

Over the years, the show has made stars of some players willing to act up for the cameras. In 2009, Bengals star Chad Ochocinco entered several catchphrases and sound bites into the pop culture lexicon. And some characters have even gone on to other reality shows. Emmitt Smith prepped for his last season on the Dallas Cowboys during the 2002 installment of “Hard Knocks.” He went on to win “Dancing With the Stars” four years later.

Tonight’s other highlights

• Scheduled events at the XXX Summer Olympics (7 p.m., NBC) include gymnastics, track and field and beach volleyball.

• Some believe that a picture frame can be traced to one of two doomed oceanliners on “History Detectives” (7 p.m., PBS).

• “Shipping Wars” (8 p.m., A&E) enters a second season.

• Amanda undergoes a delicate cleansing procedure before a blind date on “Beverly Hills Nannies” (8 p.m., ABC Family).

vA glance back at close calls on “Deadliest Catch” (8 p.m., Discovery).

vLife-and-death drama on “NY Med” (9 p.m., ABC).