O's officially add McDermott to roster for major league debut tonight (plus lineup)

MIAMI – The Orioles made a few roster moves to get right-hander Chayce McDermott from the taxi squad to the active roster. He will make his big league debut tonight and get the start on the mound versus the Marlins.

To get McDermott on the active roster, right-hander Bryan Baker was optioned to Triple-A Norfolk. To add him to the 40-man roster, right-hander Jonathan Heasley was designated for assignment.

McDermott will wear No. 60.

Over 20 games at Triple-A, he went 3-5 with a 3.96 ERA. In 91 innings, he had a 5.34 walks-per-nine-innings rate and 12.76 strikeouts-per-nine-innings rate.

McDermott leads the International League in strikeouts and is tied for the overall minor league lead.

Ranked as the O’s No. 6 prospect by Baseball America, he is No. 7 via MLBPipeline.com, which provides 60 grades on his fastball and slider and 45 for his control.

Baker had been called up from the minors June 11 and went 1-1 with a 4.32 ERA for the Orioles, throwing a scoreless inning in last night's 6-3 loss to the Marlins. Over 16 innings, he has walked five, fanned 13, and allowed a .207 batting average and .649 OPS.

Heasley was acquired by the Orioles from the Royals on Dec. 18 for right-handed pitcher Cesar Espinal. In four games with Baltimore, he allowed 10 earned runs over 5 1/3 innings. In 10 games at Triple-A Norfolk with three starts, he was 0-1 with a 2.64 ERA. 

The Orioles will try to even this series at a win each tonight after Tuesday's loss. They had eight singles in the first three innings, but then went 1-for-19 at-bat from the fourth inning on.

At 60-40, they lead the American League East by 1 1/2 games over the Yankees, who also lost last night. 

The Orioles have lost seven of their past 10 games and nine of 14. They are 11-15 since June 21. They are 13-29 all-time against the Marlins, their worst win percentage versus any other team. 

No other roster moves were announced by the club, although more news could still be coming. Jorge Mateo suffered a left arm and elbow injury last night when he collided with Gunnar Henderson going for a ground ball in the third inning. He left the game and while initial X-rays were negative, late last night he was headed for further testing with an MRI. The team has not yet announced the results of that testing. 

Jordan Westburg is playing second base tonight and Ramón Urías will be at third base. 

For the Orioles 

Gunnar Henderson SS
Adley Rutschman C
Anthony Santander DH
Ryan O'Hearn 1B
Heston Kjerstad RF
Jordan Westburg 2B
Colton Cowser LF
Cedric Mullins CF
Ramón Urías 3B

Chayce McDermott RHP