The welterweight division is the most volatile in boxing at the moment.

This past week, Andre Berto’s close, but unanimous decision over Luis Collazo in a sensational fight on Saturday in Biloxi, Miss., sent minor waves through THE RING’s 147-pound ratings.

Berto climbed from No. 9 to No. 7, trading places with Zab Judah, who hasn’t had a significant victory since he stopped Cosme Rivera in 2005. Collazo remained at No. 8 even though he lost because of his inspired effort in a fight that could’ve gone either way.

These changes are nothing compared to what’s possible next week, though.

No. 1 Antonio Margarito faces No. 3 Shane Mosley on Saturday at Staples Center in Los Angeles on HBO.

If Margarito wins, he solidifies his rating and sets up a possible matchup with No. 2 Miguel Cotto for the vacant welterweight championship. Margarito knocked out Cotto in July, Cotto’s last fight.

If Mosley wins, he would presumably move up and put himself in a position to fight for THE RING championship if he can lure Cotto into a rematch. Cotto narrowly outpointed Mosley in 2007.

Cotto fights Michael Jennings on Feb. 21 in New York, an enormous step up in competition for the Englishman.