Just a week ago, the San Francisco 49ers were discussing a potential contract extension for Aldon Smith. Despite the linebacker's roller coaster offseason issues, the 49ers felt he had turned a new leaf. However, that came to a screeching halt when Smith was released from the team following another arrest. San Francisco admits that he is not easily replaced as they question if the team has enough depth to make up for the loss.

Defensive coordinator Eric Mangini admits that it will not be easy to replace Smith simply because of just how talented he is at the linebacker position. The 49ers have a few options they can utilize to help lessen the blow. Rookie Eli Harold and Corey Lemonier are the two top candidates to jump in and help immediately. Ahmad Brooks and Aaron Lynch could also step in if the line is shifted. That might be good, but there is no doubt the 49ers have a huge hole to fill at a bad time.

"A guy like Aldon is not a guy that you just can replace," Mangini said, via ESPN.com. "He's got a unique skill set. But one of the things that we focused on defensively is building flexibility, in terms of what we can play, and then building flexibility with who's going to play there."

Meanwhile the contract extension that was supposed to be headed to Smith could be headed to Vernon Davis who is also expected to get a nice extension either prior to the season or right after. The release of Smith was a shock, but necessary as rumors continue to fly  that the linebacker had drama with the team. Quarterback Colin Kaepernick denied the idea he had been fighting with Smith prior to his dismissal.

Will Smith play again in the NFL? According to the San Mercury News, Smith is not expected to play in 2015, but there will be teams interest in him come mid-season or next offseason. The linebacker is simply too talented to allow him to sit on the market and wait. Mike Florio of Pro Football Talk is reporting that the Seattle Seahawks or the New York Giants could be landing spots for the linebacker once his business is taken care of.

Entering a critical season and in need of a bounce back year, this is not the start the 49ers wanted to have. The team is hoping to move on quickly and allow depth players to emerge as starters. Time will tell if that actually ends up happening.