Game 4 on Monday may be Nets’ last of the season. It could also be Ben Simmons’ first. Nets coach Steve Nash was non-committal about Simmons being able to suit up Monday against the Celtics, but the young All-Star went through a third high-intensity contact workout on Saturday and seems on course for Game 4. That game will be do-or-die after the Nets lost Game 3 to the Celtics 109-103 at Barclays Center. “I think it’s possible [for Simmons to play]. But I’m not sure,” Nash said. “It’s not a normal return to play being out nine months and being injured as long as he has been. At the back end of this, it’s been about two months or more.