The Red Sox are the only AL team with a higher OBP, and the only AL team with a bigger gain in OBP from 2015 to 2016. There are many ways to get on base, and therefore many ways to raise your on-base percentage, but in general drawing more walks is the best way to go about it. And if we look at the teams that have improved in walk rate, we see a pretty strong correlation with the OBP gainers.
The Rays and the Jays are the only teams that have improved on their BB% and declined in OBP. The Royals (of course) are the only team that have posted a worse BB% but improved in OBP. So, unless you are following the Royals formula and making a ton of contact with speedy, high BABIP guys, then any increase in OBP is probably being fueled in large part thanks to a bump in your BB%.
It's an intuitive concept to grasp, and it seems like everyone on the O's got the memo except for Jonathan Schoop. He actually has raised his BB% by a full percentage point this year. The only issue is that he raised it from 2.8% to 3.8%. For context, league average thus far is at around 8.4%. Walks have trended down over the last decade as strikeouts have risen, but any way you slice it, 3.8% is not good.
And yet, somehow Schoop's OBP is currently sitting at .322. That isn't particularly good, but it's average, and that's all the O's need from him. To put it into perspective, Schoop's OBP beats out teammate Pedro Alvarez (.315) despite him having a BB% almost 7% lower than Alvarez.
Schoop's inability to walk has always been troubling, but if he's found a way to get on base at a league-average rate despite his low walk rate, that eliminates arguably his biggest weakness and turns him all of a sudden into a complete player that could put up 3.0 WAR seasons at second base for years to come.
Still, that's a big 'what if'. Without good speed, a .320 OBP is not easy to sustain with a 3.8 BB%. Looking at the underlying stats, the increase in OBP has been fed by a higher average that in turn has been supported by a .335 BABIP. While Schoop hits the ball hard enough to generate an above average BABIP, his career mark of .317 indicates a batting average regression is coming. So unless he starts getting hit by pitches regularly, the OBP should come down to around .300 by the end of the season.
I did find two interesting adjustments that pitchers are making this season in response to Schoop's pitiful 2015 walk rate. First, Schoop is seeing 6.4% fewer fastballs according to PITCHf/x, which is a product of his .779 OPS vs. hard stuff / .635 OPS vs. soft stuff for his career. Second, Schoop has seen 6% more pitches in the strikezone (Zone%) this season compared to last, according to Baseball Info Solutions. In fact, his 48.8 Zone% is among the highest in baseball this season, which means that pitchers aren't afraid to give him a pitch to hit because they know he swings and misses a ton (his 17.5 SwStr would have led baseball last season if he had enough PA to qualify) and has poor discipline.
But while he has continued to swing and miss a ton, he is taking the lemons and making lemonade. He's increased his contact percentage on pitches in the zone (Z-Contact%) by almost 5%, which has been a big reason behind his overall bump in Contact%. Baseball is a game of adjustments, and you can bet that pitchers will collectively dial back that Zone% as they realize that Schoop has the ability to do damage given enough pitches in the zone.
Lastly, I thought it would be interesting to look at other players this season who have been valuable despite low walk rates. I set the WAR floor at 1.0 and the BB% ceiling at 5% and filtered to find these names.
Salvador Perez and J.T. Realmuto aren't the best comps because they get a big positional adjustment boost for being catchers. Starling Marte and Eduardo Nunez rely on their exceptional speed to get on base. Kevin Pillar fills up the WAR bucket almost entirely with his stellar center field defense. That leaves us with Adam Duvall and Rougned Odor. Both are intriguing comparisons. Odor obviously has speed but the fact that they're both second baseman who hit the ball hard brings them closer. Duvall is a more disciplined hitter but has very similar Soft/Med/Hard hit rates to Schoop.
Regardless of which is the better comp, expect Schoop's OBP to come down to around Odor and Duvall's level (in the .290 to .300 range) as pitchers adjust and his BABIP regresses.