RENTON — After a disappointing first-round exit in the playoffs last season, the Sounders talked about returning to their defensive identity. At issue was set piece defending, but also errors in the run of play, ceding late goals and defenders accumulating a spat of red card suspensions. A quarter into their MLS regular season, the Sounders (6-1-2) are blending stout defending with entertaining offense. The club has ceded a league-fewest five goals in MLS matches while averaging 2.2, across all competitions. Unexpected stats considering the Sounders are amid a center back crisis. Yeimar Gomez Andrade, one of the top defenders in the league, has been out since March 7 due to a hamstring injury. He likely won’t return to the lineup until July. Intended backups Kim Kee-hee (calf) and Ryan Sailor (knee) haven’t made their season debut because of injuries while Antino Lopez, who was signed March 17 from the club’s second division Tacoma Defiance, is still gaining experience. No worries, there’s Alex Roldan.…