In the NFL, it’s known as Black Monday, a day when coaches get canned, whether it was warranted or not, the day immediately following the conclusion of the regular season when changes are initiated. In the NBA, there’s no description to describe the day after the end, but the repercussions are similar, the usual backdrop of agendas and protecting one’s turf at play. Like every non-playoff team, the off-season in Toronto begins the moment Wednesday night’s visit by the playoff-bound Celtics is officially in the record books. Whether the coming weeks and months is a time that ushers in major changes in Raptorland, only time will tell. The team has been close in many games, only to come up short when lack of execution and lack of mental toughness were exposed. Someone has to bear the responsibility, someone eventually has to pay the price and that someone often is the head coach. Dwane Casey has been around the NBA block long enough to understand the cruel business that is the NBA, a cut-throat world where the only certainty is change. More than anyone, Casey understands the bottom-line nature of pro basketball. In Toronto’s case, the Raptors aren’t going to the post-season for a franchise-high fifth spring in a row, second under Casey’s watch. “I never once wake up worrying about a job,’’ said Casey in the hours leading up to Tuesday’s tip in Atlanta. “I know I’m going to coach. I’m a big boy. “If they (Raptors management/ownership) call the next day and decide I didn’t do a good job, that it’s my fault we’re not going in the right direction, then, hey, just let me know. I understand it’s a business, it’s part of the NBA. They hire you and the only thing they don’t put on your contract is the day they let you go. “You’re human and you don’t want to get fired. I want to continue to do the job we started out to do because I think we’re going in the right direction, but it’s ownership and MLSE’s prerogative.”