Colin Rea gets the start for the Chicago Cubs on Sunday against Miguel Vargas and the Chicago White Sox. First pitch is at 2:20 p.m. ET at Wrigley Field. The Cubs have the 16th-ranked team ERA among all league pitching staffs (3.98). The White Sox's 36 home runs rank 27th in MLB this season.

Here are three observations from the three-game series from Wrigley Field this weekend, where the Cubs swept the Cubs.

The Chicago Cubs and the Chicago White Sox will face off Friday afternoon at Wrigley Field in the first game of the Crosstown Classic this weekend.

The Chicago Cubs are teetering on the brink of disaster. That’s not exactly the expected opening line of an article about a first place team not far removed from a gloriously one-sided victory and riding high on a wave of excitement.

The City Series — which starts Friday at Wrigley Field — gets a boost as the Cubs and White Sox spent time this week debating the fandom of Chicago-born Pope Leo XIV.

Vargas, who hit a solo home run in the fourth, didn’t take kindly to the pitch and let Keller know without saying a word. He glared at Keller as umpire Jeremie Rehak walked between them.

The Chicago White Sox have placed left-hander Tyler Gilbert on the 15-day injured list with a sprained MCL in his left knee.

The Chicago Cubs called up third baseman Matt Shaw from Triple-A Iowa on Monday for the start of a three-game series in Miami, sources told the Chicago Tribune. Manager Craig Counsell hinted at the move Sunday after the Cubs swept the White Sox in the opening round of the City Series at Wrigley Field, and it will be made official Monday.