Chris Bassitt checked off a momentous personal milestone on Thursday evening against the Angels, throwing the first shutout of his career. He kept Shohei Ohtani, Anthony Rendon and the rest of the Angels offense in check all night en route to penning a two-hit masterpiece.

The right-hander had all his pitches working for him, but the effectiveness he got out of his slider was especially noteworthy.

Bassitt only threw 11 sliders in Thursday’s 5-0 win, but generated six called strikes and whiffs with the pitch. Of Bassitt’s nine strikeouts, four came by way of the slider.

“Obviously, it’s a big change of speeds,” said catcher Sean Murphy. “It’s tougher for righties just because of the angle on it and it breaks on two planes. His curveball is 12-6, and the slider allows him to just give guys another look. It’s another weapon.”

The slider was essentially nonexistent from Bassitt’s repertoire until last season. In 2020, Bassitt mixed in a couple; he threw 28 in total, accounting for just three percent of all his pitches. Even with the limited usage, Bassitt got some decent results, limiting opposing hitters to one hit in eight plate appearances.

This past spring, Bassitt continued to add polish. Sergio Romo, whose frisbee slider is among the most aesthetically pleasing in baseball, helped Bassitt work on his arm slot. Left-hander Jake Diekman helped with the grip.

With the tips from Romo and Diekman in tow, Bassitt has incorporated the pitch more often, throwing it 8.7% of the time this season. How has it fared?

So far, it’s been his best pitch.

This season, opponents have a .067 batting average and .067 slugging percentage in 30 at-bats against Bassitt’s slider. Entering Friday, Bassitt’s slider has a whiff (swing and miss) rate of 64.1%, the third-best figure for any pitch in baseball. For perspective, the only two pitches that have a higher whiff rate are Aroldis Chapman’s sinker (70%) and Liam Hendriks’ slider (68.8%).

It should come as no surprise, then, that Bassitt’s slider has a Run Value of -4, the best among all his pitches.

“I think tunneling with his fastball makes it good,” said designated hitter Mitch Moreland. “And also, him being able to throw his big curveball off it as well, because they’re closer in speed. So, he’s able to have one that goes up and one that goes down, and then one that has a little east to west movement on it as well.”

The slider still isn’t one of his primary pitches, taking a backseat to his sinker, cutter and four-seam fastball, but it's used more than Bassitt’s changeup and curveball. Given the early return on investment, it won't be surprising if Bassitt dips into that well more often as the season went along.

“Not only is it a different pitch, it’s from a different arm angle and he throws two pitches from that arm angle,” said manager Bob Melvin. “He tends to drop down a little bit more on it, but he also throws some fastballs down there, so not only is it a different look, it’s two different pitches from that look."

Versatility is the key
Coming into Thursday evening, Melvin constructed a lefty-heavy lineup to counter right-hander Shohei Ohtani. When Ohtani was a late scratch due to transportation issues and the Angels were forced to go with southpaw Patrick Sandoval, the A’s had their counter.

Jed Lowrie, a switch-hitter, assumed designated hitter responsibilities in place of Mitch Moreland. Chad Pinder was inserted at second base. Stephen Piscotty took over for Seth Brown in right field. The only left-handed hitter who remained in the lineup was first baseman Matt Olson.

That last-minute lineup change was a testament to the versatility the A’s possess. Whereas last season Oakland had a predominantly right-handed lineup, the current squad is better equipped to counter the opposing starting pitcher -- even when unexpected circumstances arise.

On Friday, with Ohtani once again scheduled to pitch, Melvin doubled down on the left-handed bats, throwing five (including Lowrie) into the lineup.

“Having those options is always better for a team, righty or lefty,” Moreland said. “Just like last night with Ohtani being scratched and them going to a lefty, a couple of us were out of the game and then a couple of us were in there, just that quick. That just shows our versatility and the complete part of our lineup. It’s a good problem to have."