Just before the start of St. Louis Cardinals Spring Training, Jenifer Langosch reported that Luke Weaver was working to expand his repertoire. Specifically, she reported Weaver wants to add a sinker and slider.
I’m admittedly wary of the slider. Keith Law noted that Weaver has never had a breaking ball of any kind, even in college. Additionally, Baseball America made no mention of one in their report upon Weaver’s call-up last season. Maybe Luke Weaver will throw a fine slider, but there’s no way to know what it will look like as of now.