The offseason program is underway with the Miami Dolphins.

Let’s open the Twitter mailbag to see what’s on the minds of Dolphins fans:

@JamesWalkerNFL are they going to let Miller carry the load out of the backfield? Never had 20 carries in any game last season.

— Ken Ciantar (@KCiantar3) May 21, 2015

James Walker: Let me answer your question in two ways, Ken. Should Lamar Miller get more carries? Yes. That was painfully evident last season when the Dolphins seemingly kept Miller on a pitch count, even when he was having a strong game. Miller rushed for 1,099 yards but probably could've had 1,300 yards if he got about five more attempts per game. Will Miller get more carries in 2015? That's a different question. For three years, Miami's coaching staff has never viewed Miller as a bell cow or workhorse running back. As soon as Miller gets up to maybe 12-15 carries, Dolphins' coaches get conservative with him. It's hard to say that philosophy will suddenly change. The Dolphins also are very optimistic rookie tailback Jay Ajayi can carry some of the load as long as he stays healthy.

@JamesWalkerNFL With Tannehill's extension he and Philbin are no longer hitched to the same wagon. Is this make or break for coach in 2015??

— Original312 (@RHeightsFinest) May 21, 2015

Walker: Yes, Dolphins head coach Joe Philbin must win this year. The roster is in place to do it and there are no more excuses. Philbin received a one-year contract extension from team owner Stephen Ross, but that was mostly window dressing. Ross and Philbin both know ownership has shown a lot of patience, especially relative to today's NFL. Philbin is 23-25 as a head coach and has zero winning seasons and zero playoff appearances. If Philbin doesn't produce a winning season in 2015, I don't see Ross continuing to stay patient.

@JamesWalkerNFL What's best suited with our current personal "a 3-4 or 4-3" defensive scheme?

— @DABestseventy2 (@DBestseventy2) May 21, 2015

Walker: This has been a constant question in South Florida, and it really doesn't matter much. The Dolphins are sticking to a 4-3 defense as long as defensive coordinator Kevin Coyle is in charge. That's what he knows and the alignment he trusts. That doesn't mean the team won't run different variations with the speed package on third down or the occasional 5-2 look against certain opponents. If second-round pick Jordan Phillips develops and plays this season, I think you could see some 5-2 or 3-4 alignments on defense. But the base will remain a 4-3.

Thanks for the good questions, Dolphins fans. If you have additional questions, comments or concerns, feel free to reach me via Twitter @JamesWalkerNFL.