The heat is on several NFL coaches — and it has nothing to do with the soon-to-be steamy dog days of training camp.The regular season is still more than six weeks away, but some coaches already face questions about their job security. For a few, such as the New York Jets’ Aaron Glenn, Tampa Bay’s Todd Bowles and Cincinnati’s Zac Taylor, slow starts could make their seats pretty toasty early in make-or-break seasons. For some others, such as Green Bay’s Matt LaFleur and Philadelphia’s Nick Sirianni, there’s not immediate pressure, but that could change if their squads don’t live up to lofty expectations and team owners ponder franchise-altering decisions.Todd Bowles, BuccaneersThrough four seasons with Tampa Bay, Bowles is 35-33 in the regular season and has won three NFC South titles. But last season’s collapse, during which the Buccaneers went 2-7 down the stretch to finish 8-9 and miss the playoffs, had some thinking Bowles’ days with the team were done.Instead, the Bucs opted to stick with him. He’ll likely need double-digit wins, a rebound performance from quarterback Baker Mayfield under new coordinator Zac Robinson and some postseason success to stay around. The Bucs’ defense — which Bowles calls himself — also must be much improved.