This is Baseball Musings, an occasional offseason column that riffs on random things found while perusing Baseball Reference, Fangraphs and other baseball sites.If asked to rattle off a list of baseball’s top players, I admit that it would take me a while before I got to Marcus Semien. That’s not to say Semien isn’t worthy of such an accolade, just that his on-field exploits in 2019 didn’t capture my attention the way they probably should’ve. That’s because in 2019, Semien became a superstar without the stardom. But shame on me for not paying better attention.Semien, 29, is among the three finalists for AL MVP. But he plays for the A’s of Oakland, who by law are generally prohibited from national attention or otherwise dwelling in the consciousness of greater baseballdom, so I’m guessing there are a lot of baseball observers who don’t realize just how good he was this past season. MORE MUSINGS: Remembering Lonnie Smith’s crazy 1989 seasonWe’ll start here: Semien was worth 8.1 bWAR in 2019. That was the fourth-best mark in baseball, behind only the Dodgers’ Cody Bellinger (9.0), the Astros’ Alex Bregman (8.4) and the Angels’ Mike Trout (8.3). Think back to the start of this column. If you were asked to name the top four position players from 2019, by WAR or any other measure, would Semien have made the list? I’m guessing not. This was Semien’s seventh season in the majors. He was a solid player before 2019, at times bordering on All-Star level, but this past season was unquestionably a breakout year (even though he still didn’t make the All-Star team).Semien played in all 162 of his team’s games, primarily hitting lead-off. He produced a slash line of .285/.369/.522 while clubbing 33 homers and driving in 92 runs, the latter of which led the team. As you might imagine, Semien’s contributions paced Oakland’s batting efforts in other key categories, too. He also led the A’s in hits (187), doubles (43), triples (7), walks (87), total bases (343), runs (123) and the aforementioned WAR.In a year when home run and RBI totals soared, Semien’s traditional counting stats weren’t all that spectacular. But the deeper you go, the more valuable he becomes — not just in the context of the A’s, but in MLB as a whole. Semien’s 123 runs scored was the fourth-highest total in baseball. His 343 total bases were also tied for fourth. He was sixth in extra-base hits (83) and 10th in runs created (128).But here’s a big one, and what arguably speaks most to his offensive value: He got on base more than almost everyone else in baseball. Semein’s 276 times on base in 2019 was second only to Bregman. That’s remarkable. I’ll say it another way: Getting on base is the point, and only one player did that more than Semien in 2019.Also important: Semien proved valuable with his glove, too, accounting for 1.5 dWAR. This is noteworthy because he was the league’s worst defensive shortstop a few years ago, but has made substantial improvements to become a Gold Glove finalist in consecutive seasons. So, as you now see, Semien has become a legit superstar. It’ll be interesting and fun to see whether he builds on this success in 2020. It’s easy to say that if Semien played in New York or Boston or Chicago that he’d be at the forefront of every baseball fan’s mind. But that’s a lazy excuse for not appreciating him. It’s easy as writers and fans to get caught up in the usual suspects or the popular storylines and overlook a good story somewhere else. This happens to some extent just about every season.Marcus Semien was a good story in 2019, and enough of my fellow BBWAA members recognized it to reward him with a spot as an MVP finalist (I didn’t have a vote this year). But I suspect I’m not alone in failing to give him his proper due. We should talk about him more.I wish I had followed him more closely in 2019. It’s always a treat to witness greatness.