Why is Nick Markakis hitting with less pop recently?

It is a fair question to ask: What has happened to Nick Markakis' power numbers and why are they down so much in recent weeks? For the 2013 season Markakis is batting .282 with 19 doubles, eight homers and 45 RBIs. He has a .336 OBP, a .377 slugging percentage and .713 OPS. He is on a pace to compile 27 doubles, 11 homers and 64 RBIs. According to baseball-reference.com, over his career, his 162-game averages in those categories are 40 doubles, 17 homers and 83 RBIs. His career slugging percentage is .447 and career OPS is .809. In 55 games in April and May, he had 12 doubles and seven homers. In 57 games since June 1, Markakis has just seven doubles and one homer. He has gone 37 games without a homer since June 24. I know Markakis is not a big home run hitter and the Orioles do not expect him to be, but these numbers are down somewhat from what we'd expect him to produce in a normal year for him. Now, we should also point out the good. He is batting .331 with a .746 OPS out of the leadoff spot. He has a respectable .274 average with runners in scoring position, is 3-for-7 with the bases loaded and is batting .301 from the sixth inning on. Markakis plays solid defense and brings a quiet intensity to the club. He's looked to for leadership even if he isn't very vocal and he is tremendously respected by his teammates and the coaches. For those that care only about the stats, this might not mean much, but it resonates within the team. He is also one of the few players in the lineup that works the count and makes pitchers work hard to get him out. He's a gamer and that does count for something. But the falloff in extra-base hits is somewhat striking. Maybe it is just part of the ebb and flow of the season and his final numbers will be fine. I also know you wouldn't have to attend many Buck Showalter press conferences before hearing him rave about something Markakis did - often something not noticed in a box score. Should there be some concern about Markakis' numbers? Maybe. Does he remain a key cog in the lineup? Absolutely. What is your take?: How do you feel about the season Markakis is having?