User blog comment:IamJakuhoRaikoben/Chapter 495: I'm Hungry As Hell, Review./@comment-141.0.14.146-20160725164520/@comment-7418318-20160725213841

Makarov thought that Jura might be able to challenge Gildarts. There was no surety about it, just the possibility. And Makarov could have been wrong too.

Case in point is Makarov's surprise about Laxus' winning.

With Gildarts being gone from the guild for such long stretches of time, it'd hardly be surprising if Makarov had only a very vague idea where his current power- and skill-levels are at.