Want some good news about Lionel Messi? You got it!
According to a report from Catalan outlet Diario ARA, the Barcelona superstar had an appointment with Dr. Ricard Plana, the main man in the Blaugrana medical staff. After a battery of exams, Plana told Messi everything has gone according to plan, and the Argentinean is free to continue his training schedule and prepare his return.
Messi's problems began in late August, when Leo joined the Argentine national team complaining of groin issues. He played hurt against Uruguay and aggravated the problem, which forced him to fly back to Catalonia. He was apparently recovered and played plenty of minutes for Barça, until he hurt his groin again in the La Liga match against Atlético Madrid, and Leo was then ruled out for three weeks.
Reading closely the various reports on Messi's injury and speaking to people with knowledge of the situations, it seems clear to me that the injury was not serious. Leo could have played through the issue until the international break, but the doctors convinced him that three weeks of rehab and smart training would be enough for him to fully recover and be able to play football completely pain-free. This was more resting than actually nursing an injury, and it has been carefully done to avoid him hurting his groin for real and missing several weeks or even a few months.
Messi will increase the intensity of training over the next few days, and he should be ready for full training once the internationals come back. He will be completely healthy to play the Champions League match against Manchester City in two weeks, and he might get some minutes in the league game at Camp Nou against Deportivo La Coruña to build his fitness and warm up for Guardiola's visit.
See, Leo? I know you're really stubborn and you love to play, but not playing hurt is actually good!