The Indianapolis Colts open training camp on July 26 at Anderson University in Anderson, Indiana. Here's a closer look at the Colts camp, which wraps up on Aug. 11:

Top storyline: The same storyline from last year, the year before that and the year before that: the offensive line. The left side is set with Anthony Castonzo and Jack Mewhort at tackle and guard. Rookie Ryan Kelly will start at center. The uncertainty is on the right side at tackle and guard. The Colts will use most of training camp to see who will man those positions come Week 1 against the Detroit Lions. Indianapolis gave up 118 quarterback hits last season, second most in the NFL. The importance of an improved offensive line is magnified now after quarterback Andrew Luck missed nine games and the Colts used five quarterbacks last season.

The Colts' season hinges on the ability of the right side of the offensive line to protect Andrew Luck. AP Photo/David Drapkin

If the starting QB does stay healthy, the Colts should be in position to win their third AFC South title with Luck. Questions remain about the offensive line and the aging defense, but Luck has proven throughout his career that he can mask many of the roster flaws when he's healthy. He missed those nine games last season and Indianapolis missed the playoffs for the first time in the Luck era. Luck didn't miss a snap because of injury in his first three seasons and the Colts made the playoffs in each of those. The Colts didn't give Luck a $140 million contract for no reason.

Player who will have fans buzzing: Phillip Dorsett missed five games during his rookie season with an ankle injury, but he's healthy and he'll be the team's third receiver behind T.Y. Hilton and Donte Moncrief. Dorsett's injury problems were rightfully the focal point of his rookie season, but his 35-yard touchdown reception against the Tennessee Titans, in which he went up in traffic to come down with the ball, showed his big-play ability and played a significant part in keeping the Colts from falling to 0-3. Dorsett will have more opportunities to show off his speed this season because so much attention will be paid to Hilton and Moncrief.

Position battle worth watching: Nothing is more important than the battle for the right-side tackle and guard positions, but the fight for third cornerback spot between Darius Butler and D'Joun Smith will be intriguing. Butler has been the third corner for each of his four seasons with the Colts, but general manager Ryan Grigson made no secret of it in February that he expects Smith to push the veteran Butler for that job in the slot. The Colts hope Smith, who dealt with knee problems during his rookie season and had a setback during the offseason, will be healthy enough to challenge Butler during training camp.

That rookie should start: Ryan Kelly became the starting center the second the Colts selected him with the No. 18 pick in the draft. He's the only player in their rookie class who will -- or should -- start. Kelly, who will be the sixth starting center Luck has had, took basically every snap with the first unit during offseason workouts.

Veteran whose job is in jeopardy: Defensive lineman Art Jones arrived in Indianapolis with a lot of hype after he signed five-year, $33 million contract in March 2014. That hype quickly turned into disappointment because Jones hasn't been healthy. Jones has 23 tackles and 1.5 sacks while playing just nine games in his two seasons with the Colts. To add to Jones' concerns: He took a pay cut to reduce his salary by $2.5 million next season, and he missed all of the offseason workouts as he works his way back from the broken ankle he suffered in the preseason last year.

Philbin's impact: The Colts' best offseason move wasn't selecting Kelly in the first round or signing Patrick Robinson to replace Greg Toler as starting cornerback. It was hiring Joe Philbin as their offensive line coach. Philbin, who didn't have much success as head coach of the Miami Dolphins (24-28), has significant history in coaching offensive lines. He had success in that role while with the Green Bay Packers and he's already making an impact with the Colts. Philbin consistently stressed to his unit to do things with speed and tempo while in practice, in meetings and even in film sessions during the offseason program.

Feeling old: The Colts fired Greg Manusky as defensive coordinator and replaced him with Ted Monachino. Monachino said the Colts will have an attacking defense, but the problem is he wants to do so with an aging unit. The Colts, who have finished in the bottom third of the NFL on defense in three of coach Chuck Pagano's four seasons, could start five players who are at least 30 years old next season. That includes 35-year-old sack leader Robert Mathis.

What fans will be saying after camp: That there is hope for the Colts' offensive line after all because they finally made it a focal point (four out of eight draft picks used on offensive linemen) and because they hired Philbin. An improved line and a healthy Luck should have them in the position to have one of the top offenses in the league next season. The Colts fell to 28th in the league in total offense last season after finishing third in that category in 2014.

For daily updates at camp, check out the Indianapolis Colts clubhouse page