This would mean Messi would probably be available to play the return leg of the Champions League quarter-finals against Paris side.
Barcelona fans will still have to wait for the doctor's official diagnosis to determine the severity of the Argentinian star's hamstring injury.
The World Player of the Year put the visitors in front on Tuesday night with a trademark left-footed finish seven minutes before half-time.
He was withdrawn at the break after pulling up with a hamstring problem.
"The club's medical services have informed that Leo Messi suffered an injury in his right hamstring," said a statement on the club's website.
"Tests will be carried out on Wednesday to determine the exact extent of the injury."
And there was more bad news for the La Liga leaders as Javier Mascherano has been ruled out for six weeks after he was stretchered off six minutes from time with a nasty-looking knee injury.
"The medical services of the club confirmed at the end of the game that the Barca number 16 has suffered a tear of the internal lateral ligament in his right knee," said another statement from the club on their website.
"Mascherano was injured in the second-half in an accidental clash with Jordi Alba, who fell on top of his leg.
"If he completes the estimated time out of six weeks, Mascherano will arrive back just in time for the final part of the season."
The former Liverpool man's absence leaves Barca short of fit defenders for the return leg at the Camp Nou next week.
Carles Puyol and Adriano have already been ruled out with long-term injuries, so the inexperienced Marc Bartra or Alex Song will likely have to partner Gerard Piqué in defence.