The New England Patriots placed running back TreVeyon Henderson on injured reserve Saturday as he deals with unexplained neurological symptoms.

The move means Henderson will miss at least the next four games. He had already been ruled out for Sunday's game against the Detroit Lions in Munich, which kicks off at 8:30 a.m. Central.

It comes eight days after Henderson revealed he had gone through what he called "an unexpected and unusual medical emergency involving a series of unexplained neurological symptoms."

No answers yet

Henderson has said his medical tests came back "positive and reassuring." He also said "the cause of this remains unknown and unexplainable."

He has not played since the Week 7 loss to Chicago.

A thin backfield

The Patriots began the week with just two healthy running backs in Corey Kiner and Lan Larison. Starter Rhamondre Stevenson has been managing a knee tendon injury from last Sunday's loss to the Green Bay Packers.

Stevenson was limited in both practices in Munich. Coach Mike Vrabel said Friday that Stevenson was feeling "pretty good." He said the same about receiver A.J. Brown, who has missed the past two games with a knee flare-up.

New England did not elevate a running back from the practice squad before Saturday's deadline. Most teams carry at least three backs into a game, so that could be a sign Stevenson will be ready to go.

Other moves

The Patriots activated center and guard Greg Van Roten and fullback Reggie Gilliam from injured reserve. They also elevated center and guard Andrew Rupcich from the practice squad for Sunday.