Taylor Decker missed the open portion of practice Thursday, leaving the Detroit Lions with a question mark at left tackle ahead of Sunday's season opener against the San Francisco 49ers.
Decker appeared on the Lions' practice report Wednesday with a finger injury, and the team signed offensive tackle Will Holden to the practice squad Thursday morning.
If Decker cannot play, the Lions could shift rookie Penei Sewell from right to left tackle.
Sewell played exclusively on the right side this summer, but was a left tackle during his two seasons at Oregon.
"I thought he did some good things (in the preseason)," Lions offensive coordinator Anthony Lynn said of Sewell.