The Collective Bargaining Agreement gave the Pittsburgh Pirates the option of pushing back this makeup game from Sunday's rainout because of the amount of days they're now scheduled to play consecutively.

It might've been wise to guarantee their struggling bullpen two days off.

Limiting the relievers' work seems unlikely with Ryan Vogelsong taking the mound Monday as he looks to keep the Colorado Rockies from winning their first series at PNC Park since 2011.

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The Pittsburgh bullpen has a 4.26 ERA that ranks among the worst in the majors after leading baseball with a 2.67 mark last season. The Pirates (23-19) had their eight-game winning streak over the Rockies (21-21) snapped Saturday when Mark Melancon allowed three runs and Jared Hughes another in a 5-1 defeat.

"We've got some guys here that we believe we can get on the right track. We've got some guys at Triple-A that we believe we can get them on the right track and they can help us," general manager Neal Huntington said. "Between the two clubs, we'll get some guys going and we'll be OK."

The bullpen got a break when Sunday's game was postponed with Colorado leading 1-0 after one inning. Under the CBA, the Pirates had the right to push the makeup to another date since playing Monday means they're scheduled for games the next 31 days. The home team is allowed to deny a next-day makeup if it's forced to play more than 24 straight days.

They elected to play it anyway, and the relievers should be busy with Vogelsong (1-1, 4.12 ERA) not expected to provide a long outing. He's made one start in 11 appearances, going five innings against Detroit on April 13.

The right-hander last took the mound Tuesday when he allowed three runs in 1 2/3 innings against Atlanta. He pitched a scoreless inning out of the bullpen against the Rockies on April 27 after posting a 5.13 ERA in 13 consecutive starts against them.

Carlos Gonzalez is 3 for 19 against Vogelsong and enters this matchup in a 2-for-32 slump over his last 10. He's hitting .183 in May, and it could've been worse had his strikeout Sunday counted.

The postponement also subtracted an off day for the Rockies, who will now play 27 days in a row. They'll send Jordan Lyles to the hill for his first start since being recalled from Triple-A.

Lyles (1-1, 7.64) was demoted April 25 after going fewer than five innings in three of his four starts. He went 1-1 with a 5.40 ERA in four starts in the minors and was originally recalled for a relief role before the rainout gave him a chance to start.

"I'll go with it and have a positive attitude," Lyles told MLB's official website. "At the end of the day it's about the Colorado Rockies and winning ballgames."

The right-hander hasn't faced the Pirates since 2013, and it's unclear if he'll have to deal with Jung Ho Kang. The infielder injured his left hand sliding into home plate in the fourth inning Saturday and was scheduled to have Sunday off.