Messi was stretchered off in Barcelona's 0-0 Champions League draw with Benfica on Wednesday after picking up a knee injury, but he appears to have avoided major damage.
The Argentina international was brought on as a substitute in the second half but was forced to withdraw with a knee problem five minutes from time after clashing with opposition goalkeeper Artur. Barca boss Tito Vilanova indicated that the knock suffered by the forward was not as bad as first feared after initial medical tests, but Messi suggested that he may be unavailable for the league clash with Betis on Sunday.
"I feel good, but I don't know if I can play next Sunday," the Ballon d'Or nominee said at a press conference at Camp Nou. "We will see."
The Argentine admitted that he had immediately feared that the injury was serious but was soon reassured by the Blaugrana doctors.
"The truth is that I didn't really think about anything, because I was in so much pain, but I feared the worst. I thought that I might have to leave the ground," Messi said. "I feared the worst when the doctors looked at it and examined me but, once they said it wasn't serious, I felt a lot more relaxed."
The Barca No. 10 was asked how he felt being played in a game with nothing riding on it, but he claimed to be happy to be on the field, regardless of the game's importance.
"When you go out onto any pitch there is always the risk something can happen to you," Messi said. "[Pep] Guardiola used to play me in these games, and as long as I can play and Tito allows me to play in these games, I will continue to do so."
Messi remains just one goal behind former German standout Gerd Muller's record number of goals scored in a calendar year but dismissed his interest in the milestone.
"As I keep on saying, the record is not an obsession for me," Messi said. "I've heard my teammates saying they are going to help me beat the record, but all of the goals I've scored are down to their help. I'm not worried about it. It would be very nice to do it, because I am so close.
"If I do it, I hope I can hold onto the record for as long as Muller, but it doesn't worry me. If I can do it, great, if I can't it's no big deal. But now I am so close I'm going to go for it."