Adrian Peterson is expected to play Monday night against the New York Giants, but the Vikings could be without their starting left tackle.

Matt Kalil missed practice for a second consecutive day Saturday after experiencing tightness in his back and is listed as questionable. Kalil received treatment during practice and said his back felt better Saturday than the previous day.

"If it keeps progressing, then yeah I'm pretty confident I'll play Monday, if I don't have any setbacks or anything," he said.

J'Marcus Webb presumably would take Kalil's spot if he's unable to play. Kalil will receive treatment throughout the weekend and see how his back responds by Monday.

"It's hard to tell with these kind of things," he said. "One day you can be fine, and the next day I could wake up stiff again. I'm just working every day trying to get as loose as I can, and hopefully I'll be ready to play Monday."

Peterson was listed as probable after dealing with hamstring tightness this week. He missed Friday's practice but did some work on Saturday.

Vikings coach Leslie Frazier said cornerback Jacob Lacey, who signed this week, likely will be active Monday night in place of A.J. Jefferson, who has an ankle injury.

CHIP SCOGGINS