12:25 PM ET

Mostert has been out since early last season with a knee injury.

The announcement was made on social media by Mostert.

It's hard to hear that you might never step on the field again. Good things happen when you bet on yourself and your faith. Work pays off. He said that he was beyond grateful.

During the 49ers first game of the season in 2021, Mostert had knee surgery and missed the rest of the season. He signed a one-year contract with the Dolphins in the off-season, but did not participate in spring practices as he recovered.

When asked about Mostert's status for the start of the season, first-year coach Mike McDaniel, who was Mostert's coach in San Francisco from 2017 to 2021, said the team wouldn't rush him back.

He expects to play Week 1 and we will not rush it. He's been working hard for a long time so he's not going to have a problem. He will be on the field when he is ready.

One of the fastest players in the league, Mostert has struggled to stay on the field over the past two years, playing just nine games. When healthy, Mostert was one of the league's most efficient and dangerous runners, with a 5.37 yards-per-carry average and eighth in percentage of rushes of 10 or more yards.

The crowded backfield in Miami needed an upgrade and he joined it. The Dolphins averaged less yards per game last season than the Texans and Falcons, but they signed two running backs and a first round pick.

While he's not expected to be Miami's feature running back, Mostert's experience with the system should provide valuable leadership in the locker room.

In March, Mostert said that he tried to implement his role when he was with the 49ers. I'm going to beat him out. I want to win. I'm going to show everyone that they made a mistake when they signed him and didn't sign me. It is more like "Hey look, we're all brothers, we're in this together and this is how we are going to operate." I would like to see you win and I would like to see me win.

I told Eric Studesville, the running backs coach, that I'm going to help you feed your family and that's what I told him when I first arrived. I've lived with that since I was in San Francisco. He made that happen in the room. I'm going to make sure that the guys that aren't familiar with the scheme and the play calls are made aware of that.

In March, Mostert said that he was ahead of schedule with his rehabilitation and that his doctor said he was the fastest-healing patient he had ever seen.

His return will make Miami's new-look offense even more threatening as he and Edmonds are both capable of running and receiving the ball out of the backfield.

I really like the idea. I like the idea of me and Raheem in the backfield. I was a big fan of his game before he got injured, so I wanted to watch his explosion. He's the fastest running back in the league when he's at his best, so I think it brings a sense of explosion to the offense, and we both have good yards per carry. I believe that we can look to do something to help the offense.