Seattle @ Colorado preview

Last Meeting ( Aug 3, 2015 ) Seattle 8, Colorado 7

Highly regarded prospect Jon Gray makes his major-league debut on Tuesday, when the Colorado Rockies host the Seattle Mariners in the second contest of a three-game series. Gray was the third overall selection of the 2013 draft and nearly won a rotation spot in spring training before being optioned to Triple-A Albuquerque.

The 23-year-old Gray has pitched only 276 minor-league innings but the Rockies feel he is ready to make an impact. "We felt like we'd see him at some point this year, and that day has arrived," Colorado manager Walt Weiss told reporters. "I'm excited to see him out there, and I'm sure he is too, but we've got to remember he's still a young kid and he'll go through some of the growing pains that young players go through." Seattle posted an 8-7 victory in Monday's series opener as Nelson Cruz continued his torrid production by homering for the fourth straight contest and extending his hitting streak to 14 games. Cruz has gone deep nine times during the streak to reach 30 for the third time in his career.

TV: 8:40 p.m. ET, ROOT (Seattle, Colorado)

PITCHING MATCHUP: Mariners LH Vidal Nuno (0-1, 2.02 ERA) vs. Rockies RH Jon Gray (NR)

Nuno is drawing a spot start in the rotation hole created by the trade of J.A. Happ to Pittsburgh. He is starting for the first time this season and has a 3-13 record and 4.08 ERA in 31 major-league starts. Nuno is 0-1 with a 2.70 ERA in two career outings against Colorado.

Gray overcame a slow start at Albuquerque and went 6-6 with a 4.33 ERA in 21 appearances (20 starts). He struck out 110 batters in 114 1/3 innings and didn't last longer than five frames in any of his last four turns. "Confidence carries over from good outing to good outing, and when you have a few good ones in a row, you start to feel really good," Gray told reporters. "Then there's a really low chance that you're going to go out there and not get a quality start."

WALK-OFFS

1. Rockies CF Charlie Blackmon recorded four hits on Monday and is 9-for-21 with four doubles and one triple over his last five games.

2. Seattle LF Seth Smith was hitless in three at-bats in the series opener and is 2-for-22 over his last seven contests.

3. Colorado 2B DJ LeMahieu struck out in all five at-bats in the opener following a stretch during which he notched at least one hit in 22-of-23 games.

PREDICTION: Rockies 11, Mariners 9