The Los Angeles Angels, who had at least a share of the American League West lead for more than two weeks last month, will play the Kansas City Royals, who have led the American League Central for more than two months, on Sunday Night Baseball (8 p.m. ET, ESPN/WatchESPN).

Here are some of the key storylines about the game, including a look at scheduled starters Hector Santiago and Yordano Ventura.

Things have changed for Santiago since the All-Star break

Santiago (7-6) has struggled in five starts since the All-Star break. His ERA was 2.41 before the break and is 5.13 since. His opponent slugging percentage was .360 before and is .509 since. He allowed a home run every 29.7 at-bats before the break; it’s one per 18.3 at-bats since the break.

His performance with runners in scoring position has fallen off significantly, as the chart indicates.

Despite the post-All-Star Game drop-off, Santiago strands more runners on base (86.0 percent) than any other starting pitcher. He and Zack Greinke (85.5 percent) are the only pitchers to strand 85 percent of runners this season.

Santiago has cut down his walk percentage of 10.3 percent the last two seasons to 7.4 percent this season. And he is pitching in front of one of the best defenses in baseball: The Angels turn about 70 percent of balls in play into outs, among the best in the major leagues.

Two pitches key against left-handed batters

Santiago is dominating left-handed batters with his cutter and slider, which he throws nearly one-third of the time.

His miss percentage with those pitches is 28 percent compared with 15 percent with other pitches, and his hard-hit average with those pitches is 9 percent, compared with 20 percent with other pitches.

The Royals’ Eric Hosmer has a .294 batting average and a 1.039 OPS against Santiago in his career, but Hosmer is hitting .212 with a .553 OPS against cutters and sliders this season.

Royals’ pitching

Yordano Ventura’s fastball averages 95.9 mph, third fastest among starting pitchers this season, behind Noah Syndergaard and Nate Eovaldi.

Ventura (7-7) is allowing a .326 batting average with runners in scoring position (12th-highest among pitchers with at least 15 starts) and a .344 batting average with runners on base (third-highest, minimum 15 starts).

In his last six starts, Ventura has a 5.56 ERA, opponents are hitting .271 against him, and he has 29 strikeouts to go with 15 walks. But the Royals have averaged 6.5 runs in those starts, and he is 4-1.

One Angels hitter Ventura might want to be wary of is Albert Pujols, who is 4-for-8 in his career with a home run against him.

Pujols showing offensive revival -- in some ways

Pujols has hit 31 home runs, his first 30-home run season since 2012, but his batting average (.253) and his on-base percentage (.312) would be the lowest of his career.

The shift is working against Pujols this season. He has had 188 plate appearances with the shift on (second to Edwin Encarnacion among right-handed batters). He is hitting .200 on ground balls and short liners with the shift on and .247 on those balls with the shift off.