The Miami Dolphins are halfway through their preseason, and we’ve seen both good and bad.

Here is a look at whose stock is rising and falling in Miami:

Falling

1. Dallas Thomas, guard: Thomas earned his way into the starting lineup with a strong spring and summer in Dolphins camp. But he erased many of those good vibes with an awful outing Saturday against the Tampa Bay Buccaneers. Thomas was manhandled by Tampa Bay defensive tackle Gerald McCoy in Miami’s 20-14 win. Thomas allowed a sack, a tackle for loss, another hit on the quarterback and had a false start. Thomas has yet to start a regular season game and now has major questions if he’s ready to handle the grind of a 16-game season. Veteran free-agent guard Shelley Smith worked with the first team this week in place of Thomas, who will try to earn his way back with the starters.

2. Running game: Two weeks into the preseason, it’s still unknown if Miami has improved its 26th-ranked running game from a year ago under new offensive coordinator Bill Lazor. The Dolphins are getting little push up front and running backs are being hit early near the line of scrimmage. Miami starting running back Lamar Miller finished with 3 yards on three carries against Tampa Bay. The Dolphins as a team had minus-5 rushing yards at intermission when starters and key reserves were in the game. Miami’s passing game is having success this preseason. But if opponents eventually figure out the Dolphins can’t run effectively, that will make Miami very predictable and easier to stop on offense.

3. Secondary’s tackling: Miami’s secondary, in general, is not a concern. However, the poor display of tackling raised some eyebrows and particularly caught the attention of Dolphins head coach Joe Philbin. Starting safeties Jimmy Wilson and Louis Delmas both displayed poor tackling on Saturday. Some of it was due to poor fundamentals and some due to overaggressiveness. Delmas said after the game that Miami’s defense will have a chip on its shoulder. This group must shake the tackling rust before the regular season.

Rising

1. Matt Moore, backup quarterback: Give Moore a lot of credit. Last week, the Dolphins shook things up by adding competition (Brady Quinn) for the No. 2 quarterback job. Moore, who suffered from a shoulder injury most of training camp, didn’t seem all that thrilled by the addition. But Moore responded like a true professional by going out and having a strong preseason game against Tampa Bay. Moore led a pair of scoring drives and was 13-of-19 passing for 158 yards with one touchdown. Moore virtually solidified the No. 2 quarterback job behind starter Ryan Tannehill with one preseason outing.

2. Receiver depth: Something has to give at receiver for Miami. The depth has this position has shown up constantly during training camp, and we also saw it in the Dolphins’ second preseason game. Backup receivers Brandon Gibson, Jarvis Landry, Rishard Matthews, Damian Williams and Armon Binns combined for 11 receptions Saturday night. Not everyone in this group will make the team. The Dolphins might want to consider trading one of these backup receivers in order to gain depth at a weaker position. Wide receiver should not be an issue for Miami this season.

3. Terrence Fede, defensive end: Fede makes this list for the second week in a row. He continues to flash to the point where I believe the rookie seventh-round pick will make Miami’s 53-man roster. Fede recorded two tackles, a sack and a tackle for loss against the Buccaneers. He also is showing his worth on special teams as an athletic big man who can run the field. The motor and athleticism are there. If Fede can get his technique down, he could develop into a contributor.