The Eagles’ good preseason injury luck didn’t quite see them through Sunday’s season-opening 32-17 victory over the Washington Redskins.

Starting defensive tackle Malik Jackson rode a cart to the locker room late in the fourth quarter, and afterward Jackson was sighted wearing a protective boot. Eagles coach Doug Pederson said Monday that Jackson suffered “a significant injury” that will require some time to heal. Pederson said a decision on whether to place Jackson on injured reserve and sign another defensive lineman will hinge on test results that weren’t available when Pederson held his day-after news conference at noon Monday.

Jackson, 29, was the Eagles’ most heralded defensive free agent signing, getting $30 million over three years, with $17 million guaranteed. The team had been looking forward to teaming him with All-Pro DT Fletcher Cox, to keep Cox from being double-teamed so much. They weren’t able to work together much in training camp, as Cox recovered from a foot injury suffered in last season’s playoff loss at New Orleans. Now it’s unclear when they will play together again; Jackson got in 34 snaps on Sunday.

The Eagles have a defensive tackle on their practice squad, Bruce Hector, who appeared in eight games last season. They also could decide to play a few of their defensive ends — Vinny Curry, certainly, and probably Brandon Graham — inside on obvious passing downs. In that case, the potential roster move could be for a defensive end — such as ex-Eagles Chris Long or Connor Barwin.

Jackson’s injury is to his lower leg or foot, but the Eagles have not given specifics. A lis franc foot sprain or an Achilles tendon tear are among the likely possibilities.

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