The Miami Dolphins will begin the on-field portion of their offseason program Tuesday. The team will hold nine organized team activities during the next three weeks.

Here are several things to keep an eye on for the Dolphins:

No. 1: Ryan Tannehill's return

Quarterbacks often get the most attention this time of year, but many will be watching Tannehill particularly close following last year's season-ending knee injury. Tannehill suffered an ACL and MCL sprain that did not require surgery, but it knocked him out of the team's final three regular-season games and Miami's playoff loss to the Pittsburgh Steelers. Tannehill will wear a fitted brace to protect his knee. We get to see the first signs this week on whether that will impact or change Tannehill's play.

No. 2: Early position battles

Who will take the lead for Miami in several key position ballets? Positions such as outside linebacker (Koa Misi vs. Raekwon McMillan), left guard (Ted Larsen vs. Isaac Asiata) and nickel cornerback (various players) are up for grabs. Football in shorts won't fully determine who wins these jobs. But it will establish early leaders heading into training camp.

No. 3: How will Miami use its linebackers?

The Dolphins enter OTAs in an interesting spot at linebacker. They have three potential starters -- Lawrence Timmons, Kiko Alonso and McMillan -- who have most of their experience at middle linebacker. The issue is two of these players must move outside this season. Alonso and McMillan are the likely candidates to play outside linebacker. However, Dolphins defensive coordinator Matt Burke said the staff will remain open-minded and could change the plan week to week. This will be the first peek at Miami's initial plan.

No. 4: Which rookies will shine?

The Dolphins, on paper, may not have drafted a Week 1 starter. But rookies Charles Harris, McMillan, Asiata and Cordrea Tankersley are among the young players who have a chance to earn a sizable role this season. The proving ground starts this week in OTAs. Rookies must prove they have the playbook and scheme down and can apply it on the field against veteran teammates.