Lamont Peterson says he’s recovered from a shoulder injury heading into his next fight Jan. 20. (Jahi Chikwendiu/The Washington Post) District boxer Lamont Peterson has earned considerable respect throughout his career for his choice of quality opponents. The former world champion’s next fight is no exception: Peterson is set to face Errol Spence Jr. on Jan. 20 at Barclays Center in Brooklyn. Spence (22-0, 19 knockouts) is the reigning International Boxing Federation welterweight champion after traveling to Sheffield, England, to defeat Kell Brook in Brook’s home town via 11th-round knockout. Peterson (35-3-1, 17 KOs) is a former world champion at 140 pounds but will have gone 11 months without a fight when he steps into the ring against Spence. [Lamont Peterson saluted with day in his honor in Washington] The bout will be the main event for a card airing on Showtime, promoters Lou DiBella and Tom Brown announced recently. “I would say mentally and physically, better than ever,” Peterson, 33, said early Wednesday afternoon in a telephone interview before a news conference at Barclays Center featuring both fighters and their respective camps. “I’m in a good place right now. Excited about the fight, as always. Any chance I can get to fight, especially on the big stage, I’m excited. Just having fun right now.” Peterson last fought Feb. 18 in Cincinnati, beating David Avanesyan by unanimous decision to claim a secondary World Boxing Association belt he relinquished not long after so he could fight Spence. Protracted layoffs are nothing new to Peterson, who routinely has fought once a year, but this time he’ll be coming off an injury he did not disclose publicly until after defeating Avanesyan. Peterson hurt his left shoulder roughly a year ago while training and elected not to visit a doctor. Upon being examined following his last fight, Peterson indicated several doctors informed him he would require surgery. Peterson wound up heeding the advice of a third specialist, who told him the torn deltoid, confirmed in an MRI exam, could heal properly with rest and rehabilitation. “Nothing going on there. I’ve been testing the shoulder a bunch,” Peterson said. “A big deal