Sanchez, who was acquired in a trade with the Royals for Jeremy Guthrie on Friday, will make his first start for the Rockies in Monday's series opener against the D-backs at Chase Field.
The lefty is no stranger to the National League West, having played for the Giants from 2006-11, before being traded to the Royals. The American League wasn't kind to Sanchez, as he went 1-6 with a 7.76 ERA and struggled with command, walking more batters (44) than he struck out (36) in 53 1/3 innings.
"If there is a next step that he can ascend, to take him to a different level, it's throwing more strikes than he has," Rockies manager Jim Tracy said after the trade. "It'll be interesting to see in relation to the format, how he gravitates to that."
If Sanchez again struggles with walks, it could make for a rough return to the NL West against an Arizona team that has not only won six straight games at Chase Field, but has been on a tear of late, winning four of its last five games overall. The D-backs have scored 9.4 runs per contest in those five games.
During the D-backs' weekend sweep of the Astros, Arizona scored 33 runs while also going 19-for-39 (.487) with runners in scoring position -- something the D-backs will look to continue against the Rockies.
"Just getting better pitches and laying off the marginal pitches," D-backs manager Kirk Gibson said. "As a hitter, when you get runners in scoring position, you can kind of suffer from anxiousness and it can work against you, because you want to get the guy in. In those situations you want to have a good approach, try to use the middle of the field and not get too greedy.
"The most important thing is getting a good pitch. We've done a better job at laying off the pitches that are in the zone that aren't in our strengths."
Rockies: Pomeranz expected to miss next start
Lefty Drew Pomeranz will likely have his Tuesday start pushed back, Tracy said Sunday. Pomeranz experienced soreness in his left arm during his start Friday.
"I don't know that [a Tuesday start] is a possibility just yet," Tracy said. "He's going to play catch tomorrow in Arizona to determine the extent. Is it just a push-back or is it anything else?"
It is unclear whether the Rockies will turn to righty Carlos Torres or call up a pitcher from the Minors to take the mound Tuesday against the D-backs.
D-backs: Kennedy starts series opener
Right-hander Ian Kennedy is scheduled to take the mound Monday against the Rockies. He is coming off one of his best starts of the season, an eight-inning effort against the Reds during which he allowed just one run while striking out seven.
Kennedy is 2-1 with a 2.77 ERA in nine career starts against the Rockies. He last faced Colorado on June 5, when he threw six shutout innings and struck out a season-high 12 batters.
The season series between Arizona and Colorado is tied at 4-4. The Rockies dropped two of three at Chase Field in early June.