We shouldn't be too surprised that Arian Foster latched on to a NFL team. We also shouldn't be that surprised that it took this long. Recovering from a torn Achilles he suffered last season, the four-time Pro Bowler had no real reason to sign with a team after his release from the Houston Texans. In turn, no team had much of a reason to sign him. 

Now that Foster is apparently fully recovered and the Miami Dolphins needed to find a running back with some sort of previous NFL-level success, it seemed to be a marriage made in heaven. 

With Foster now in South Beach, the Dolphins have definitely solidified their running back situation. However long that lasts, especially when taking into account Foster's injury history, remains to be seen. 

What we do know is that there are widespread fantasy implications that go along with this relatively large mid-July signing. Here are a few of them. 

1. Jay Ajayi is about as irrelevant as they come

If there's one thing that we must take away from this signing it's that the Dolphins obviously weren't sold on Ajayi to be their lead ball carrier after losing Lamar Miller to free agency in March. Some of this has to do with his lackluster performance as a rookie. Though, there's definitely concern within the organization that Ajayi's knee simply won't hold up long term. 

Ajayi fell to the fifth round of the 2015 NFL Draft (originally considered a second-round pick) due to concerns over a bone-on-bone knee injury he suffered back in 2011. In reality, the injury itself might not be a short-term issue. Instead, the issue many had leading up to last year's draft was that Ajayi might not hold up over the long term. That has to be a concern when looking at him in dyno leagues. Now following the signing of Foster, this concern floods over to re-draft leagues. 

In terms of the on-field performance we saw from the Boise State product as a rookie, it simply wasn't too much to write home about as a rookie. Ajayi put up just 187 yards on 49 attempts (3.8 average) in nine games. That's not necessarily someone we should bank on in re-draft contests. Despite all this, Ajayi's ADP currently has him as a mid fifth-round pick. Sell. Sell. Sell.  

2. Don't bank on Foster, but make sure to roster him 

Foster most definitely can't be relied on as a RB1. People made that ill-fated decision last season, and it came back to bite them big time. Such is the nature of the beast when relying on a running back that has missed half of his team's games over the past three years. Simply put, we're not at the point in the evolution of fantasy football where this type of injury risk makes sense. 

As with every player in the fake football world, value is all about draft status. Philip Rivers most definitely isn't a good pick in the first four rounds. But if you're able to nab him in Round 10, the value he brings to the table suggests he will live up to expectations. 

This is somewhat the position we find Foster in heading into the 2016 season. There are a good 20 running backs that I personally would feel better drafting ahead of him. Instead, he has to be considered in the group of backs that include Ryan Mathews, Jeremy Langford, Melvin Gordon and Chris Ivory — all running backs with question marks heading into the 2016 campaign. Based on pure ADP, this would put Foster the territory of the eighth round. 

If that's the case, you will then be left pondering whether Foster's injury history affords him the benefit of the doubt. Based on the names likely available here, our recommendation would be that you take the risk and go with the former All Pro performer. After all, you're likely not relying on him to be anything more than a bottom-run FLEX or solid bench option. 

3. Help for Ryan Tannehill? 

When Tannehill has help behind him in the backfield, he's simply a vastly different quarterback. 

These aren't outstanding numbers, but the yardage figures (277 passing yards per game) tells us a story of a quarterback that has more success down the field when his running game is going well. On the other hand, 27 less passing yards in game where his running backs failed to hit the triple-digit plateau. 

This might not seem like a big deal, but based on fantasy points per game, the difference here was Tannehill being a bottom-rung QB1 in 12-team leagues and a mid-tier QB2. Think about that for a second when taking into account his current ADP as the 22nd quarterback off the board.