World Player of the Year Messi damaged a hamstring just over a month ago and although he had been given the all-clear by medical staff he was unable to play in Wednesday's Champions League defeat by Bayern Munich.
Busquets, who has been suffering from a minor groin problem, also missed the Bayern game as Barca were thumped 3-0 in the semi-final second leg for a humiliating 7-0 aggregate reverse.
"Leo Messi and Sergio Busquets, who had not been able to work at the same pace as their team mates in recent sessions, trained normally," Barca said in a statement on their website.
Victor Valdes was still suffering pain in his left foot and forward Pedro missed training because of a bout of gastroenteritis.
Barca have an 11-point lead over last season's champions Real Madrid in second and need five points from their remaining five games to secure a fourth title in five years.
If Real fail to beat Real Valladolid at home on Saturday a Barca victory against Betis would be enough as they would be at least 13 points ahead with only 12 left to play for.
- Sports & Recreation