This story was excerpted from AJ Cassavell’s Padres Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

Here's something I learned a long time ago: Never, ever underestimate the competitiveness of a big league ballplayer.

Duh, right? Their very livelihood is tied directly to wins and losses -- and just how capable they are of contributing to the former. So of course, they're competitive.

But it's more than that. These guys want to win at everything. And everything they do is a competition.

So when Joe Musgrove and Mike Clevinger happened to be throwing simultaneous bullpen sessions last Wednesday morning in St. Louis ... it was game on.

"We got up there, I was like -- let's just have fun with it and get into that compete mindset," Musgrove said. "So we started playing a game of H.O.R.S.E."

Yes, H.O.R.S.E. Like the basketball game you probably played in your driveway ... or on that mini basketball hoop hanging in your college dorm ... or throwing crumpled-up papers into that nearby trash can.

The rules are simple enough: You call a pitch and execute it? The other guy has to match it. If not, he gets a letter. Spell out H.O.R.S.E. and you lose the game. These rules were strict, too. If you dotted a slider on the outside corner, that might be a big league out pitch. But if you had called a back-foot slider -- well, no credit for you.

"And we both have a lot of pitches," Musgrove said. "So we're calling everything."

Pitching coach Ruben Niebla was the arbiter of the proceedings. The rest of the Padres’ rotation looked on, as well. Musgrove and Clevinger had to shorten the game from H.O.R.S.E to P.I.G., because both kept hitting their spots.

"Joe popped up the question randomly, and next thing you know, it was just pitch for pitch for pitch, and we were just matching each other over and over," said Clevinger. "We were at like 40 pitches each in our bullpen, and we had to call it."

Oh, and remember how competitive these guys are? Well, naturally, there was some controversy. Clevinger threw a rising two-seamer (which is not part of Musgrove's arsenal). He dotted it. Musgrove couldn't match it. That tied the game. But with the bullpen session coming to an end, Musgrove won it when he executed a four-seamer up-and-in to a lefty.

Both agree that Musgrove won (P.I.G. to P.I.). But, "with an asterisk," according to Clevinger, who claims he wasn’t given a proper rebuttal. Then again, that's sort of beside the point.

"Both of us were like: 'Those were some of the best bullpens we've ever thrown in the big leagues,'" Clevinger said. "Just because it took your mind off all these mechanical cues you're usually working on, and it just let you compete."

This was 10 a.m. on a Wednesday morning, mind you. The Padres had recently traveled halfway across the country to the Central time zone. To their body clocks, it was 8 a.m.

They could be excused for being a bit sluggish. But suddenly, this was a competition. And when it's a competition, well, these are professional athletes. There’s no room for sluggishness.

"We both had better bullpens than we would've had at 10 a.m. before a day game had we not done that,” Musgrove said. “I don't think it's something that you want to do every time, because you end up throwing a little harder, and it's a little more intense, you feel a little sore after. But a short morning like that, it was perfect."

Can't argue with the results, can you? Musgrove carried a no-hitter into the eighth inning in his start on Friday night. Then Clevinger returned from the injured list with three innings of one-run, one-hit ball on Sunday, striking out five before he reached his pitch limit.