There were many other factors contributing to that contrast, but superstition doesn't want to hear explanations.
Or, maybe it was the sound and sight of the ball off Mercer's bat. Or the zip on it from deep in the hole. Maybe it was all of it. But, at some point, the Bucs decided it was time, and they crossed that invisible line from Barmes to Mercer.
Mercer himself certainly believed the time had come. The 2008 third-round Draft pick had spent most of the 2012 season in a Pirates uniform but also on the Pirates' bench, playing a lot less than observing -- and that was by design.
"Going to different parks, just watching the game, helps more than you can imagine," Mercer said. "You're prepared. You literally go through being out there, in your mind, and when you get the opportunity, you want to make the most of it. I have so far."
Mercer came from Indianapolis, this time to stay, on May 15 with a .333 average. In 38 games with the Pirates, he is hitting .286 -- and that stands out on a team that is being carried by pitching and has no one carrying a higher average than Andrew McCutchen's .287.
That offensive modesty may have also contributed to the switch. When they were pounding the ball more lustily last season, the Pirates could afford to accommodate Barmes' lighter bat because of his defensive excellence.
"No question, Clint Barmes has done some tremendous things for us defensively," said Neal Huntington, the general manager who had signed him to a two-year, $10 million deal as a free agent prior to the 2012 season. "He's been hot and cold with the bat. Jordy has come up here and made the plays that need to be made and has swung the bat a little bit better."
Echoed Hurdle, "We know the impact Barmes has had defensively up the middle. And I do think there'll be times his bat can still play and help us."
Still, rather than departing after this season to pass on the position to Mercer, Barmes had to take a seat and watch him take over.
It was supposed to be a subtle transition, with Mercer getting more playing time than just what was needed to give someone else an occasional rest. The 25-year-old Okie began to pop up regularly against left-handed starters, to the point where Hurdle had to deny having entered into a straight platoon.
"It's not a platoon. They're sharing the position to some degree, with Barmes getting a higher percentage of the playing time," Hurdle had said the first week of June.
Then Mercer got some looks against right-handers, too. And he became immovable. He has started 13 of 14 games since June 12, including the last 11. The Bucs have won eight of those 11, the same number in which Mercer has hit safely.
And Mercer tends to not waste his hits. He has a definite MOB mentality, batting .409 with men on base, one of the top figures in the Major Leagues.
"Seems like I've been doing that ever since I got into pro ball," Mercer said. "I don't know the reason. I couldn't tell you. I just have a knack for coming up with big hits in big spots."
Significantly, his latest hit came in the ninth inning on Wednesday, breaking a 2-2 tie in the Pirates' 4-2 win in Seattle -- the one that vaulted them into a first-place tie with St. Louis in the National League Central; the two teams share the absolute best record in the big leagues. That was Mercer's 11th RBI in 126 at-bats -- not earth-shattering, but one more than Barmes has in 164 at-bats.
"He can add something to the lineup," said Hurdle, modest praise from someone who recognizes that this game is a grind and avoids overboard acclaim for brief spurts. "He's still finding his way."
Barmes is left dealing with going from full-time status to not even part-time. He is in that limbo between being a good teammate and hurting because he is no longer starting.
"I get it," Barmes said. "If they think they've found someone better, I know that's how it works. I've been challenged with the bat. This has actually given me the freedom to do extra work on fixing it, and I can feel the results."
He also feels he is still a regular shortstop and is not ready to embark on the life of a utility man, a second baseman for a few innings today, maybe a shortstop again for an inning tomorrow.
Maybe Hurdle is just riding a hot horse with Mercer, hoping the extra work Barmes does now will pay off when he is needed again.
"There may come a time when Barmes gets more time at short, as the league figures out Jordy a little bit and he has to make an adjustment," Huntington said. "It's just nice to have two guys we feel are very capable of playing Major League-caliber shortstop, and Hurdle will put both into position to be successful."
That position is shortstop. And now it's Mercer's time.