A monster has loomed just behind the Boston Celtics all season with its fangs bared, ready to attack and mangle the Celtics beyond repair, once and for all. After a 5-9 start, the Celtics lost Rajon Rondo for eight games. The wheels could have tumbled off, but the Celtics went 6-2 with Avery Bradley as a starting point guard.  The Celtics later lost five straight games entering the All-Star break, and a killer eight-game road trip awaited in March. Boston won its first five after the break and finished the nightmare-ish March schedule with a 12-5 record. The Celtics have always seemed to answer the call this season.

But that monster is closing in on the Celtics again, with a deathly April that promises to be at least as challenging as March. The Celtics play 11 times in the next 15 days, with bouts against the Miami Heat, San Antonio Spurs, Chicago Bulls, Orlando Magic, Indiana Pacers, New York Knicks, Atlanta Hawks and Philadelphia 76ers. The only three games that aren’t against playoff games during the next hellacious stretch come as a back-to-back-to-back, all on the road against the Toronto Raptors, New Jersey Nets and Charlotte Bobcats.

“The thing is, we don’t know,’’ Rivers said about the upcoming stretch (via ESPN). “I wish I knew. I don’t have any idea how the guys are going to react to it, how their bodies are going to react to it. If we think we see something, we’ll change the lineup to get different guys more rest. Or we will sit a guy here and there. Who knows? I wish there was a formula for this. This stretch is going to be hard. That’s why it’s so nice going to into this stretch having won games.”

The Celtics are currently 1.5 games ahead of the Sixers for the Atlantic Division lead, just one game in the loss column behind the Pacers for the East’s third seed. But the monster is approaching yet again. Can the Celtics keep fending it off?