Gates rejoined the Chargers this past weekend and signed a one-year contract. The 38-year-old was summoned after fellow tight end Hunter Henry began the season on the physically unable to perform list with an ACL injury.
"I've always been optimistic about playing in a game, whether I was injured or not here -- it didn't matter," Gates said, per ESPN. "So, I think I'm well aware of the preparation that needs to be put in throughout the week to go play a game at the highest level possible. With that being said ... it just depends on how I feel leading up to Sunday."
Chargers coach Anthony Lynn admitted that he is keeping a close eye on Gates.
"I'm going to watch him closely this week," Lynn said. "I want to know where he is conditioning-wise. We know that he can help us. That's why we brought him back. I don't know how much yet, but we'll see."
Gates joins a tight end group that includes starter Virgil Green and backup Sean Culkin.
An eight-time Pro Bowl selection and three-time All-Pro, Gates had 30 receptions for a career-low 316 yards and three touchdowns in a reduced role in 2017.
Gates is the Chargers' all-time leader in receptions (927), receiving yards (11,508) and touchdowns (114), with his touchdown total an NFL record for tight ends.
He has caught 87 touchdown passes from Philip Rivers, the most in league history for a quarterback-tight end tandem.
Gates also has 21 games in his career with more than 100 receiving yards, one of only seven tight ends to achieve that feat.