Moss, 35, has played last 10 seasons in Washington, but he had just 10 catches for 116 yards in 10 games last season. He earned a little more than $1 million last season and is now a free agent.
Gruden said the team is leaving the door open for Moss to return for an 11th season with the team.
"We're keeping a close eye on Santana," Gruden said at the NFL owners meetings in Phoenix. "You know, that's something that we know where Santana is and he knows where we are, and something may work out down the road."
Last season, the Redskins finished No. 11 in passing yards and No. 27 in passing touchdowns. If Moss does re-sign, he will likely be behind Pierre Garcon, DeSean Jackson and Andre Roberts on the depth chart.
During his 14-year career, Moss has amassed 732 catches, 10,283 receiving yards and 66 touchdowns.
Earlier this week, Gruden said the team has not ruled out selecting a quarterback in the upcoming draft. Washington has the No. 5 pick in the draft.
- Paul Palladino