Murray told ESPN's Ed Werder that he will have an MRI on the foot Monday.
Murray didn't start the second half but got a snap on the second possession and gained 3 yards on first down before being taken out for Felix Jones.
It appeared the move irked Murray.
"I was trying to (get back in), that was their decision to (take) me out," Murray said. "It's a long season. It's only the fifth game, and I have to do what's best for the team."
Murray rushed 14 times for 93 yards and no touchdowns. Jones rushed for 92 yards on 18 carries and one TD, his first since the 2011 season opener.
As an offense, the Cowboys rushed for 227 yards, the most ever allowed by the Ravens and the most for the Cowboys since they gained 294 against the St. Louis Rams on Oct. 23, 2001. That day, Murray came off the bench to rush for a franchise-record 253 yards.
This time he started, and in the first quarter he rushed for 72 yards on eight carries, the seventh-most first-quarter rushing yards in franchise history.
"It was going well and everybody was on the same page and we just got to keep it going," Murray said.
Jones left the game with cramps but later returned.
Cornerback Morris Claiborne, the team's first-round pick, tweaked his knee on a touchdown pass and also later returned.
Defensive end Sean Lissemore suffered a high ankle sprain in the first half and didn't return.