Messi left Barcelona's goalless Champions League draw with Benfica on a cart in the 84th minute after colliding with visiting goalkeeper Artur Moraes.
The sight of their star player being taken off the pitch silenced the Barca fans, but there was relief soon after with the club confirming the injury was no worse than a bruised left knee.
Messi worked in the gym as his team-mates trained outside today, and said he still had a chance of playing at the weekend.
"I feel fine, but I don't know yet if I will be available for Sunday," he said at a promotional event at the Nou Camp today, reported on the team's official website and in AS. "I'll see. I am grateful for all the messages of support I have received."
Messi said he was hurt when he struck Moraes, but then tried to score with a curling shot before falling to the ground and clutching his knee.
"I thought it was the last shot I was going to have for a long time," he said. "So I decided to gamble and hit it."
Admitting he feared the worst, he added: "The truth is I did not think about anything because all I could feel was the pain. But in a moment I thought the worst. When it was shown it was not a severe injury I was calmer."
Messi's involvement in last night's game has been a major talking point in light of the injury he suffered as the match was essentially meaningless to Tito Vilanova's men, already assured of top spot in Group G.
But Messi said he never let the fear of injury affect his approach to the game, and that he preferred to stay sharp by playing.
"Something similar could have happened in training or anywhere else," he said. "Whenever you walk onto a pitch there is a risk."
The 25-year-old went into the game one goal shy of Gerd Muller's record of 85 in a calendar year and there were suggestions the Argentina forward had only played in order to chase the milestone.
However, Messi said the record was not as important to him as was being made out.
"As I have always said, for me the record is not an obsession," he said.
"My colleagues have said they will help me and with them, I am not worried.
"It would be great, and hopefully if I do it, it will stand for a long time like Muller's, but it's not something I worry about. If it doesn't happen, it doesn't matter. But we are close so we will try."
Messi also downplayed the potential detrimental affect an injury to him could have on Barcelona.
"They would continue to play with or without me," he said. "There are plenty of other players."
With the result unimportant to Barca, Vilanova has been forced to defend his decision to send Messi on as a 58th-minute substitute.
"We talked about the possibility of him playing for 30 minutes. He's a player that likes to play," said the Barca boss.
"He's not focused on breaking the record that everyone is talking about, if that were the case he would have played against Alaves (in the Copa del Rey last week) and the full 90 minutes against Benfica.
"Playing is part of his physical training."
Vilanova was adamant he would not change the way Messi was handled.
"Should we sub him out every time we're leading 3-0 in case he picks up an injury?" he added.
"We've never behaved this way. I'd make the same decision (to play him) seeing that he can get injured at any moment."
Vilanova made a host of changes for last night's match, several of them enforced, but Messi's apparent let-off was not the only good news on the injury front this morning.
Andres Iniesta, Alexis Sanchez, Jordi Alba and Dani Alves all took part in training with the rest of the squad, while Eric Abidal was able to return to the field for lighter workouts.
Barca could now face the likes of Porto, Arsenal, AC Milan, Shakhtar Donetsk and Galatasaray in the Champions League round of 16, although Vilanova does not have a preference.
"Whoever we play against will be a big team," he said.
"The round of 16 is always complicated.
"We did what we had to do, we wanted to finish first and have that small advantage of playing the return leg at home."