Regression, defined as a return to a former or less developed state, is a word thrown around a lot in baseball. When a season is so long – when there are thousands and thousands of data points to collect – there’s no reason for fans and analysts of the game to jump to early-season conclusions about a batter or pitcher, only to see those same players regress to their mean.

Sometimes though, things change. Sometimes a return to former play doesn’t occur because a player developed, hitting the ball well or throwing it with more velocity. Good numbers from a surprising source doesn’t always mean regression is about to occur. Perhaps that player is in store for a good season. The goal of these articles is to analyze and see whether or not this is true.

If you missed last week's report, you can peep it here. If you're ready to see this week's group, keep on readin'.

Christian Yelich, Miami Marlins

Over the last 14 days, Christian Yelich has been on fire, hitting to a .400/.491/.480 slash and scoring 10 runs. He’s now batting .333 on the year, and is tied for third in the bigs in runs scored.

The young Marlin hasn’t historically been a bad hitter, and has a career .298/.379/.404 slash on 354 plate appearances to back that up. But his .453 BABIP this year ranks second in all of Major League Baseball among qualified hitters, and while his line-drive rate is high and his fly ball rate is low, he’s certainly going to see a drop in production. It’s just a matter of when.

Currently, our metrics have him listed as a below-average outfielder the rest of the way, based on predicted future production and replacement-level capabilities. If you're buying, you may want to second guess that thought.

Devin Mesoraco, Cincinnati Reds

Once upon a time, Devin Mesoraco was a sub-.240 hitter – like, way below .240 – and the city of Cincinnati wasn’t interested in what he could become. But so far this year on 38 plate appearances, Mesoraco’s sporting a .515/.553/.970 slash with three dingers and 11 RBI. Devin Mesoraco is leading the Reds in runs batted in, people. And yes, that includes Joey Votto, who has more than double the number of plate appearances.

Like Yelich – actually, even more so – this production is credited to a high BABIP. Mesoraco’s career average BABIP has been .266, and this year it’s soared to .583.

His batted ball profile is solid, but I’m more inclined to think – know – he’ll regress more towards his career-long mean. He certainly could post one of the best years of his career given his experience, but don’t expect him to be the best hitter in the game.

Josh Donaldson, Oakland Athletics

Donaldson’s now hitting .272 on the year, and that’s after a week that featured a .370 average on 30 plate appearances and a .409 BABIP. It looks as though, however, things have simply equaled out compared to the start of his season – his season-long BABIP rests at .310, which is actually only two points lower than his career average.

One area where Donaldson could regress a bit is with his power, as his 2014 ISO is 48 points higher than what he’s seen throughout his career. So while his average could remain in roughly the same spot (lower than 2013 based on his lower BABIP), be prepared for more singles than extra-base hits.

Aaron Harang, Atlanta Braves

Any regression report is going to be full of BABIP data, and that continues with Aaron Harang. The Braves righty has been fortunate to see a .143 BABIP against so far this year, which is second highest in the league among relevant pitchers. His velocity hasn’t changed much, and opponents are hitting to a similar enough batted ball profile that Harang has seen in the past. If there’s anyone willing to buy Harang in fantasy, selling him now wouldn’t be a terrible idea at all – his xFIP is getting close to 4.50.