LEADING OFF: DeGrom ailing, Swihart’s new start, when Vlad?

A look at what's happening around the majors today:

BOUR BLUNDER

Angels slugger Justin Bour looks to improve his baserunning after yet another blunder on the bags. He failed to run out a popup in a tie game in the eighth, and the Mariners alertly let the ball and turned it into an easy, inning-ending double play. Seattle wound up winning 5-3.

"There's no excuse for it. It's terrible," Bour said.

Last Saturday at Wrigley Field, Bour singled in the first inning and tried to advance on an overthrow. Bour lumbered toward second, slid in and was called safe. But convinced he was out, he simply left the base and began walking back to the dugout, and was tagged by the Cubs' Javier Baez halfway between second and first.

CHECK HIM

Mets ace Jacob deGrom will have an MRI on his right elbow after the NL Cy Young Award said his arm has felt sore. DeGrom is leaving the team in St. Louis to get examined back in New York, and the team is putting him on the injured list.

"We're not sure what it is," manager Mickey Callaway said.

The 30-year-old deGrom, who had Tommy John surgery in 2010, began this season with two dominant outings. But he lost his last two starts while allowing a total of nine runs on 13 hits — including five homers — and five walks in nine innings.

DeGrom signed a $137.5 million, five-year contract right before opening day.

NEW HOME

Blake Swihart gets a chance to jump-start his career after Boston traded the catcher to Arizona. The 27-year-old was cut by the Red Sox this week after going 6 for 26 in 12 games.

Diamondbacks general manager Mike Hazen worked in player development and amateur scouting with Boston when Swihart was selected in the first round of the 2011 draft. Swihart became one of the team's top prospects, but his offensive production hasn't matched the hype.

NUMBERS GAME

Oakland slugger Khris Davis goes into the game against Toronto with a .247 batting average after an 0-for-4 night. This is familiar territory for Davis — he's finished at exactly .247 in each of the last four seasons.

NOT SO FRIENDLY

Zack Greinke has posted a win at every current National League ballpark except one. The Diamondbacks star will try make it a clean sweep when he starts at Wrigley Field. Greinke is 0-2 with an 8.31 ERA in five starts at the Friendly Confines.

Yu Darvish (1-2, 6.11) starts for the Cubs and goes for his second straight victory.

HOW SOON?

Still no word on when super prospect Vladimir Guerrero Jr. will make his major league debut for Toronto, but it could be real soon. He is 7 for 17 with two homers, six RBIs and no strikeouts in five games for Triple-A Buffalo.

The son of a Hall of Famer, Vladdy Jr. batted .381 with a combined 50 extra-base hits at four levels in the minors last year.

"I don't know when he's coming, I really don't," Blue Jays manager Charlie Montoyo said before his team opened a weekend series at Oakland.

"We have the No. 1 prospect in baseball and it will be pretty cool when he gets here," he said.