The Miami Dolphins have been the definition of mediocrity in recent seasons. It is indicative in their 8-8, 8-8 and 7-9 records over the past three years under coach Joe Philbin.

Perhaps the biggest issue is Miami put together a roster filled with solid -- but not elite -- players. But the Dolphins finally got the game-changer they were seeking Sunday by agreeing to terms with free-agent defensive tackle Ndamukong Suh. ESPN NFL Insider Chris Mortensen reports the deal is worth $114 million with $60 million guaranteed.

The Dolphins made Suh the highest-paid defensive player in the league -- surpassing Houston Texans defensive end J.J. Watt -- and the investment is worth every penny. Signing Suh makes sense for the Dolphins on so many levels. He cleans up many of Miami's issues on defense.

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The Dolphins were 24th against the run last season, and defensive tackle was their biggest need. Suh, who helped lead the Detroit Lions to the NFL's No. 1 run defense, immediately fixes Miami's run defense and plugs its biggest hole.

A strong case also can be made that the Dolphins now have one of the top defensive lines in the NFL. Suh and Pro Bowl defensive end Cameron Wake are two of the best at their respective positions. Fourth-year defensive end Olivier Vernon registered 18 sacks the past two seasons, and Earl Mitchell is a solid No. 2 defensive tackle. The Dolphins also have former No. 3 overall pick Dion Jordan coming off the bench as a pass-rusher. Despite Jordan's flaws, he has enough talent to make an impact next season.

Suh brings a mean streak to Miami that its defense lacks. He also brings national relevance, which cannot be ignored. Dolphins owner Stephen Ross likes to make splashy moves and is spending about $400 million in upgrades to Sun Life Stadium over the next two seasons. Ross and the Dolphins need an elite player like Suh who puts fans in the seats.

The only downside is this major move ties up most of Miami's free-agent spending. The Dolphins were a flawed team last season and still have needs at linebacker, safety, cornerback, guard and possibly tight end and receiver, depending on what happens in the next week or two with the contracts of Charles Clay and Mike Wallace. Mortensen reports Suh will get $60 million over the first three seasons of his contract, which means most of these needs must be filled in the draft.

But that is a price worth paying to secure one of the NFL's most dominant defenders. Suh is a free agent who doesn't come around often, and the Dolphins were fortunate to make this landmark deal.

I recently asked Dolphins offensive tackle -- and former Lions teammate -- Jason Fox what Suh brings to the table, and Fox had nothing but good things to say.

"He's obviously a dominant player," Fox said. "He's one of the best defensive tackles, if not the best defensive tackle in the NFL. He's a game-changing type of player. He's not the 'rah-rah' guy, and he speaks up when he feels like it's necessary. He's one of the guys that leads by example. He's a hard worker, and obviously that shows."

Suh is the type of elite player who can turn Miami’s run of 8-8 seasons into 10-6. The Dolphins need more than one elite player to win a championship, but simply getting over the hump and into the playoffs next season would make the large investment in Suh well worth it.