After Wednesday’s bombshell that Danny Ainge is retiring as the Celtics’ President of Basketball Operations and Brad Stevens is moving from the bench into Ainge’s vacated role, Boston now needs to find a new head coach.

The Celtics brass said that search begins immediately. The Celtics haven’t been in this position often over the last 17 years, hiring just two coaches — Doc Rivers and Stevens — during that span.

It is Stevens’ first major task in his new front office position to help select his successor, and many questions arise as to which direction Stevens will go in as he picks his replacement. Will he choose someone with a vast amount of head coaching experience? Will Stevens decide to bring in a former NBA player that will have more sway with Boston’s younger stars?

Here are five options that have a realistic chance of becoming the 18th head coach in the history of the Celtics:

Chauncey Billups
Things could come full circle for Billups, who was drafted by the Celtics with the No. 3 overall pick in 1997 before being shipped out of Boston by Rick Pitino just 51 games into his career.

That obviously proved to be a mistake as the five-time All-Star point guard enjoyed a 17-year career, which included winning an NBA title and being named Finals MVP in 2004 with the Detroit Pistons. That sort of playing pedigree will be held in high regard by today’s players.

Billups joined the media once his playing career ended, but he put that aside to become a first-year assistant coach with the Los Angeles Clippers this season. Billups might need a little more seasoning on the bench, but he was known as a savvy player who could possibly make the leap to a head coaching gig.

Lloyd Pierce
Let’s start with the bad news about Pierce first. He couldn’t last three full seasons with the Atlanta Hawks as he was fired after 34 games this season with a 14-20 record. The Hawks immediately turned things around after Pierce’s departure and are now in the Eastern Conference semifinals. Pierce reportedly couldn’t get along with Hawks star Trae Young, which is certainly a bad sign since the Celtics need to cater to their two young stars, Jayson Tatum and Jaylen Brown when choosing their next coach.

Now for the good news about Pierce. He has spent 12 years in the NBA with five different organizations serving various roles. He has a solid background in player development, which is something held in high regard by Stevens.

Stevens spoke highly about Pierce when the Hawks decided to can the 44-year-old saying he always learned something from watching Pierce’s teams and respected his leadership on and off the court.

Sam Cassell
Cassell checks both the former player box and the experienced coach box. The former point guard played for 15 seasons in the NBA, concluding with a stint with the Celtics as he played a role off the bench to help the franchise capture the 2008 NBA title.

Cassell jumped right into the coaching ranks in 2009 and has been an assistant coach for three different teams. He has been groomed by Rivers, serving on the former Celtics coach’s staff with the Clippers and now this season with the Philadelphia 76ers.

Cassell has a good blend of experience to lean on and he seems well prepared to take on an elevated role as a head coach.

Kara Lawson
The Celtics are an organization known for their history, so it would come as no surprise if they made history by tabbing Lawson as the first-ever female head coach in the NBA.

Lawson, who had a decorated playing career at Tennessee and in her 13 years in the WNBA, was on Stevens’ staff with the Celtics for the 2019-20 season. Lawson then left last July to take the reins of the Duke women’s basketball program.

Lawson coached in just four games with the Blue Devils before their season was shut down due to the COVID-19 pandemic. Whether Lawson wants her tenure at Duke to come to a sudden end is anybody’s guess, but she does have the backing of NBC Sports Boston Celtics analyst and former player Brian Scalabrine to become the next Celtics coach. Stevens has also talked glowingly about Lawson’s coaching ability in the past and Lawson quickly gained the respect of the Celtics players as well.

Ime Udoka
Udoka isn’t a household name yet, but very well could be in the future. Udoka bounced around the NBA and the D-League and played overseas. Maybe the best thing going for Udoka is he spent seven years as a San Antonio Spurs assistant coach under Gregg Popovich, who has been widely regarded for some time as the NBA’s top coach.

Udoka spent the last two seasons with the 76ers and Brooklyn Nets, and Stevens might see Udoka’s experience as an asset for the team going forward.