The Los Angeles Angels suffered a potentially crushing blow Wednesday night when they lost ace Garrett Richards for the next six to nine months with a torn patellar tendon in his left knee.

Richards’ injury couldn’t have come at a worse time for the Angels, who currently hold a two-game lead over the Oakland A’s in the American League West with an MLB-best 76-50 overall record. With the right-hander sidelined for the rest of the season, the Angels’ rotation suddenly is much less threatening, especially in the context of a five- or seven-game playoff series.

However, rookie Matt Shoemaker did his best to ease those concerns Thursday night, guiding the Angels to a 2-0 victory and four-game road sweep of the Boston Red Sox.

The outing arguably was Shoemaker’s best of the season, as he no-hit the Red Sox through 6.2 innings before finishing with one hit allowed over 7.2 scoreless frames. The 27-year-old right-hander struck out nine batters and walked one in the game, throwing 79 of 116 pitches for strikes.

Manager Mike Scioscia offered high praise for Shoemaker following the game (via Alden Gonzalez of MLB.com):

He goes out there with his stuff, and he thinks his stuff will get hitters out. And he really has the confidence that it is. With that composure he has, and that poise, it gives him a sense of confidence where he’s not going to be intimidated. He’s not afraid to fail. He trusts what he can do, and he’s having a terrific season for us.

After picking up his 12th win of the season, Shoemaker, who signed for $10,000 in 2008 after going undrafted out of Eastern Michigan University, is now tied with Masahiro Tanaka for the major league lead among rookies, and he also sports an impressive 3.56 ERA and 102-19 strikeout-to-walk ratio through 103.2 innings.

Specifically, Shoemaker has been rolling since the All-Star break, with a 5-2 record, 2.25 ERA, 0.78 WHIP and 40-4 strikeout-to-walk ratio over his last 40 innings. He’s allowed just four home runs during that span while holding opposing hitters to a .190 batting average.

Furthermore, a deeper dive into the right-hander’s numbers this season, particularly his 3.43 FIP and 3.13 xFIP compared to his 3.56 ERA, reveals that his success is for real rather than rooted in luck.

Shoemaker’s 1.1 HR/9 is right in line with the 1.1 HR/9 he posted over seven seasons in the minor leagues, and neither his BABIP (.297) nor strand rate (74.4 percent) suggests he’ll endure a significant regression. His 1.65 BB/9 may seem unsustainable compared to his 2.3 BB/9 in the minor leagues, but it’s worth noting that Shoemaker posted a 1.4 BB/9 over 184.1 innings at Triple-A Salt Lake in 2013.

So what’s made Shoemaker so successful this season?

For starters, the right-hander boasts three major league-quality pitches in a four-seam fastball, slider and splitter, and he’s thrown each of them between 22 and 25 percent of the time this season.

Shoemaker averages 91.43 mph with his fastball, which is roughly league-average velocity, but the pitch features 10.46 inches of vertical movement, which ranks 28th among all starters who’ve thrown at least 200 four-seamers this season, per Baseball Prospectus’ PITCHf/x leaderboard. Meanwhile, opposing hitters generally have struggled against the pitch, as they’re batting just .240 with a .230 BABIP.

At the same time, Shoemaker’s fastball is arguably his least effective pitch, as he’s posted a rough 39.6 percent ball rate—compared to a 27.57 percent strike rate—this season while allowing opposing hitters to slug .453 with four home runs.

Shoemaker’s slider represents his second-best offering, registering in the 81-82 mph range with good depth (2.31 inches of vertical movement, to be exact). He’s throwing it 28 percent of the time to right-handed batters this season, who are collectively batting .222 with one home run and a 38.75 percent whiff/swing rate, per the PITCHf/x leaderboard.

That brings us to Shoemaker’s splitter, which is regarded as one of the best in the major leagues and undoubtedly the right-hander’s best offering.

Shoemaker’s splitter averages 6.03 inches of horizontal movement, tying him with Charlie Morton for the 13th-best among big league starters. However, it’s the pitch’s additional 3.74 inches of vertical movement, which ranks eighth in the major leagues, that make it special.

While Shoemaker’s fastball command can vary, he has proved to be adept at consistently locating his splitter down in the zone. It’s the reason why opposing hitters are swinging at it 63.35 percent of the time this season, the third-highest swing rate behind Tanaka and Alex Cobb, and whiffing on 46.75 percent of those swings.

Unsurprisingly, Shoemaker’s splitter is his go-to pitch with two strikes, as he’s throwing it 54 percent and 44 percent of the time to right- and left-handed batters, respectively. Overall, opposing hitters are batting just .147 with 60 strikeouts against the pitch.

Shoemaker’s inconsistent command of an underwhelming fastball normally would be disconcerting. However, with a pair of standout off-speed pitches—the splitter is nearly a double-plus—that break in different directions within the same velocity band, the right-hander has been able to offset some of those fastball-related issues. More importantly, both offerings have helped him to turn over lineups multiple times in a given outing, which in turn has allowed him to work deeper into games.

None of the Angels’ pitchers can fill Richards’ shoes in terms of his stuff and success. But with a playoff berth on the line, it goes without saying that the club will need its remaining starters to step up in his absence.

While Shoemaker certainly has pitched like an ace over the last two months, it’s still unreasonable to think that the 27-year-old rookie can be the savior of the Angels’ rotation—at least any more than he has been.

However, with continued success, Shoemaker should help take some of the pressure off the team’s other starters, specifically veterans Jered Weaver and C.J. Wilson, over the remainder of the regular season.

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