If Patriots’ offensive coordinator Bill O’Brien does depart to take over the job as head coach at Penn State, it would leave a void on the coaching staff, but would create some intriguing possibilities for New England going forward.

Much of the talk would likely center on the possible return of former offensive coordinator Josh McDaniels. McDaniels, who is the offensive coordinator in St. Louis, cut his teeth with the Patriots as an assistant from 2001 until 2005 before becoming the Patriots offensive coordinator in 2006. He was OC in New England for three seasons before taking the head coaching job in Denver and then moving on to become the OC in St. Louis. However, it’s expected that the entire Rams’ coaching staff will be shown the door at the end of the season, making his return a possibility if the job opens up.

There are some possibilities on the current staff, including tight ends coach Brian Ferentz, a younger assistant who has been part of the New England staff since 2008. The son of Iowa coach Kirk Ferentz (who was a former assistant under Belichick) he started with the Patriots as a coaching assistant in 2008, moved to offensive coaching assistant the following year and became an offensive assistant in 2010. He was officially promoted to tight ends coach at the start of this season, and has helped youngsters Rob Gronkowski and Aaron Hernandez become two of the best young tight ends in the game.

Another interesting possibility would be Pat Hill, who worked with Belichick in Cleveland and was recently let go by Fresno State. Hill was part of Belichick’s staff from 1992 through 1995, serving as Cleveland’s tight end and offensive line coach.

There’s always the chance that the Patriots would go without a coordinator — they’ve done it on several occasions, including this year, when they did not name a defensive coordinator. On the offensive side of the ball, it wouldn’t be out of the realm of possibility to not name an offensive coordinator, but give more responsibility to someone like Ferentz, let him learn on the job, and if he flowers, officially name him the OC in a year or two. One other possible wrinkle worth mentioning — O’Brien is also the team’s quarterbacks coach, and the Patriots could split the jobs again going forward.