CANTON, Ohio – The Miami Dolphins lost to the Dallas Cowboys, 24-20, Sunday night in the Hall of Fame Game. It was the first of five preseason games for both teams.

Here is what we learned about Miami:

Lamar Miller looked good in his debut as Miami’s feature running back. The second-year player rushed for 21 yards on two carries. Miller was decisive and hit the holes fast for nice gains. Miller also fumbled the handoff on the first play, but quarterback Ryan Tannehill was charged a turnover for the exchange. Otherwise, Miller had a good showing and was even trending on Twitter in the first half.

Miami’s defensive line has proven to be arguably the team’s deepest unit in training camp. That depth was on further display Saturday as the Dolphins sat out defensive linemen Jared Odrick, Olivier Vernon and Randy Starks. Backup Derrick Shelby and No. 3 overall pick Dion Jordan played well. Shelby led Miami with two sacks while Jordan was aggressive and finished with two tackles and two quarterback pressures. It appears Miami’s defensive-line rotation is in good shape.

We didn’t see much from Tannehill as he was 2-for-5 for 11 yards in limited playing time. Tannehill had his two completions to tight end Dustin Keller and receiver Brandon Gibson. Tannehill was without his two starting receivers: Mike Wallace (groin) and Brian Hartline (calf).

Overall Miami's tackling was poor. The starters whiffed a few times and the backups were worse. This has to be something that irks Miami’s coaching staff. The Dolphins have only practiced in full pads a few times so far in training camp, mostly due new collective bargaining agreement rules. Miami head coach Joe Philbin may have to step up the intensity in practice to improve the tackling.

It was mixed results for Miami starting linebacker Philip Wheeler. Wheeler struggled early in his limited playing time. On the first drive, Dallas tight end Dante Rosario beat him for 18 yards. He also missed a tackle in the open field on Cowboys tailback Lance Dunbar. Although he did read a running back play and had a tackle for a loss on the same drive. Wheeler was a major free agent addition for Miami this offseason when he signed a five-year, $26 million contract.

With the backup receiver spots wide open, Chad Bumphis tried to make a move up the depth chart Saturday night. Bumphis led the Dolphins with five receptions for 85 yards and has made strong plays in training camp. He also showed his inexperience, however, by making a costly mistake on a dropped pass in the second quarter that led to a DeVonte Holloman 75-yard interception return for a touchdown. To make the 53-man roster, players like Bumphis must be consistent.

Miami’s left tackle spot continues to be a position to watch. Starter Jonathan Martin and backup left tackle Dallas Thomas both had their issues against Dallas. Martin whiffed on Dallas linebacker Kyle Wilber on one play that allowed Wilber to pressure Tannehill. Dallas backup defensive end George Selvie gave Thomas headaches on the second team. Much of Miami’s success on offense this season will depend on consistency at left tackle.

Miami backup quarterback Matt Moore had a pretty good night. He was 19-of-29 for 238 yards, with a late touchdown and an interception on the Bumphis drop. Moore was able to move the offense and showed why he is one of the best backup quarterbacks in the NFL.

A player on the roster bubble who finally showed up was backup tight end Michael Egnew. He had four receptions for 52 yards. Egnew, a third-round pick in 2012, showed some of the things he did in college by getting vertical down the field to make catches. But he also had a drop in this game. Egnew is dangerously close to getting cut this year and must continue to make plays.