This is Stu later on in the series. After his last appearance in Sinnoh he undergoes self-improvement training. This is his attire while traveling through Unova, having started over with just his Empoleon, where he'll run into his rival Geo again, thus reigniting their rivalry again (though this time Jodi isn't around for him to hound). Despite his "self-improvement training", he proves to still be something of a meathead, having not learned much of anything from his past mistakes and still has a very "might makes right" mentality. So, needless to say, he won't fare any better against the hero as he did in the past.