Brown was shown a straight red card just before the hour mark after appearing aim a kick at Neymar in Tuesday night's UEFA Champions League clash.
Martino played it with a straight bat when asked if Neymar overreacted at the Brown incident, with Cesc Fabregas scoring a late winner for the visitors.
"I couldn't see with certainty what happened so I don't want to give an opinion," insisted Martino.
"But certainly playing with 10 men for 35 minutes against Barcelona is something to think about when analysing the game."
Martino was happy with the way his side coped without the injured Lionel Messi, admitting it was their hardest game of the season.
"We obviously prefer to play with Messi but when he is unavailable his absence cannot be used as an excuse," added Martino.
"We have some excellent players. This match was the most demanding so far, Victor Valdes made important saves for us."