Jim Caldwell has been here before, trying to steady a wobbling team, clinging to the fringes of hope. It’s all on him, he says again and again, as if that should be comforting for Lions fans. It’s not. It’s confounding and concerning, and the repetitiveness is alarming. If Caldwell and his ailing quarterback have another comeback in them, it’s difficult to see. And if they don’t, it’s hard to justify bringing Caldwell and his staff back. Yes, he signed a contract extension before the season, although the terms were never revealed. Honestly, it shouldn’t matter. The latest debacle, a 44-20 loss in Baltimore, dropped the Lions to 6-6, and if they complete the collapse and miss the playoffs, it would be time for a coaching change. GM Bob Quinn should be ready then to bring in his own guy, although it would immediately shift the pressure to himself. At some point, responsibility has to translate to accountability, and in his four seasons here, Caldwell has been spinning in place. From a terrific 2014 debut of 11-5, the Lions have gone 7-9, 9-7 and now 6-6, and 0-2 in the playoffs. You can tie some issues to injuries, especially during the four-game losing streak to close last season, when Matthew Stafford played with a dislocated finger. Now he has a bruised right hand and is stuck behind a battered offensive line. But other teams are handling more-significant injuries. The theory was, with the Packers’ Aaron Rodgers sidelined and a weak late schedule, the Lions would churn to a strong finish. The theory is getting squashed with every miserable start – zero first-quarter touchdowns the past four games — and every inexplicable gaffe.