​Tennessee Titans finished off the third week of training camp, and the competition is heating up across the roster, making it easier to identify the players fighting for the final spots and those solidly on the bubble.The physicality picked up, and the Titans finally got some live reps against the San Francisco 49ers in both practice and the first preseason game; some players who likely sit on that roster bubble did show up and flash. Unfortunately, that wasn’t the case for everyone, and some players struggled.Here is a look at the bubble watch after three weeks of practice.OffenseThe wide receiver battle will definitely go down to the end of camp. The Titans have built a solid group, and the competition has been fierce for the final few spots behind the five who are locked in. Xavier Restrepo continues to flash, making it harder to keep him off the roster.Running back appears to be becoming clearer by the day, although Julius Chestnut is taking advantage of Kalel Mullings missing time. Tennessee did add a running back to the roster on Saturday, so it will be fun to watch heading into the joint practice with Seattle.Tight end David Martin-Robinson has had a solid camp and may be working his way into the third tight end role. Now, with Jaren Kanak out for the season with a torn pec, he is likely close to solidifying his role.But all was not positive for the offense. Along the offensive line, things are starting to clear up, with Austin Schlottmann and Fernando Carmona holding the inside track to start. Behind them, there is a battle. Neither Jackson Slater nor Cordell Volson looked good against the 49ers; Slater does offer some positional flexibility, which could help his chances. At tackle, it became clear that Austin Deculus isn’t the answer; not only did he get ejected from the joint practice, he was also awful against the 49ers in the game, giving Brandon Crenshaw-Dickson the inside track.DefenseThe defensive line has looked strong and should be the defense’s strength, and some players on the roster bubble have stepped up. Tennessee signed veteran Khalen Saunders last week, and he came in and made plays. If he continues to shine, this could put Solomon Thomas or rookie Jackie Marshall on the bubble. Edge Jaylen Harrell suffered a torn ACL against the 49ers and will miss the season on injured reserve, opening up a potential path for another player, such as Malik Herring, to make a push.In the secondary, Tennessee made some wholesale changes last week and is churning the roster in search of some more depth. One of those signees, Mario Goodrich, has come in and made plays early on, giving him a bit of a boost heading into Week 4.Special teamsKicker Joey Slye quieted doubters with a tremendous outing against the 49ers both in practice and in the first preseason game. If he continues that performance, the Titans’ specialists are set.Unfortunately, there weren’t many plays made in the return game during the first preseason game, and it will