In the opener of a four-game series Monday, the Rockies (85-70) pounded the Phillies 10-1 for their fourth straight win and handed the Phillies (78-78) their season-high tying fifth straight loss.
Shortstop Trevor Story returned to the Rockies lineup for the first time since he suffered right elbow inflammation last Monday and went 2-for-5 with two doubles. Story has 80 extra-base hits and became the fourth NL shortstop to reach that mark joining Jimmy Rollins (88) and Hanley Ramirez (81) in 2007 and Ernie Banks (82 in 1955, 81 in 1958 and 80 in 1960).
"We're full throttle right now," Story said. "It's a great position to be in. These games really do matter. We're not where we want to be, but we feel like we will be in a few days."
Jon Gray, who supposed to start on seven days' rest Tuesday, instead started on Monday and worked seven innings when left-hander Tyler Anderson was scratched from his scheduled start due to shoulder soreness.
Bettis (5-2, 5.18) last started on Aug. 12 and was then moved to the bullpen where he has made six appearances totaling 8 1/3 innings. Bettis has worked in low-leverage situations and will be pitching for the first time since Sept. 13 when he worked one inning and threw five pitches.
Rockies manager Bud Black said he expects Bettis to throw between 30 and 50 pitches. He threw 30 pitches in 1 2/3 innings on Sept. 9.
Bettis is 2-0, 1.93 in six games (four starts) against the Phillies, whom he last faced in 2016.
The Phillies have been in a major tailspin since mid-August. They've lost 16 of 22 games this month and are back to .500 for the first time since April 10.
Vince Velasquez (9-11, 4.59) will start for the Phillies. He's 2-0, 3.95 in five starts against the Rockies and 1-0, 3.27 in two starts at Coors Field.
The right-handed Velasquez has been far more effective against right-handed hitters, limiting them to a .204 average and .598 OPS in 309 plate appearances. Lefties are hitting .282 with a .870 OPS against Velasquez in 300 plate appearances.
In his last start Thursday at Atlanta, Velasquez wasn't involved in the decision in Philadelphia's 8-3 loss. He gave up five hits and three runs in three innings. Velasquez has not gone more than four innings in each of his past three starts and is 0-1, 12.00 in those outings, allowing 16 hits and 12 runs in nine innings.
Velasquez threw 73 pitches in four innings Sept. 9 at the New York Mets, 44 pitches in two innings against Miami on Sept. 15 and 57 in three innings in his last start. The Phillies are very analytically inclined, but manager Gabe Kapler said Velasquez's recent short outings are performance-related and not based on any metrics.
"What I've shared with all of our starters and this is also somewhat true for our relievers is if you are the best option, all things considered, to get the next hitter or three hitters out, you will go back out," Kapler said. "And so, for Vince, when he's the best version of Vince, he's hard to take out of a game. I literally have to think about reasons why to take him out. I'm not putting any artificial limitations on Vince."