Injuries have been an issue for Blackmon. He had a broken foot that ended his 2011 season early, a turf-toe issue that delayed the start of '12 and a knee infection that scuttled his chance to make the team out of Spring Training this year. But Blackmon went to Colorado Springs and proved himself ready. The Rockies chose him over Tyler Colvin and non-roster prospect Corey Dickerson.
"There are a lot of guys doing well, and Charlie's performing really well down there," Weiss said.
Blackmon plays all three outfield positions and can be used as a starter. The Rockies have been using Eric Young Jr. in right to replace Cuddyer, who missed the past three games while trying to let the injury heal. When Blackmon starts, Young will return to his role as a spark plug off the bench.
It's not clear where Weiss will fit Blackmon into a batting order that's scuffling. Regular leadoff man Dexter Fowler singled at the end of Saturday's two-hit shutout at the hands of Cardinals ace Adam Wainwright to end his string of 20 hitless at-bats. Fowler has batted second with Young in the lineup. Blackmon could slot in as the leadoff man or in other spots in the lineup.
"We'll get [Blackmon] involved, absolutely," Weiss said. "I'm not sure exactly what our lineup will be tomorrow. We'll have to think about that.
"Charlie can fall into a few different spots in our lineup. He's a pretty versatile guy. He works counts. He draws walks. He runs well. He'll hit the ball in the gap, too."
The plan was for Blackmon to arrive in St. Louis on Saturday night and be ready for Sunday afternoon, when the Rockies will try to win the finale in the three-game series.
Cuddyer, hitting .319 with seven home runs and 23 RBIs, knew he was going to have to show improvement Saturday or face going to the DL. It didn't take long in the batting cage to figure which would happen.
"I took about six swings off the tee and knew that I wasn't going to be able to go," said Cuddyer, who discovered the injury in 2004 with the Twins and played through it when it flared in 2011. "You don't ever want to feel like you're leaving your teammates. But injuries happen."
Cuddyer's DL placement will be retroactive to Thursday, which would make him eligible to return May 24.
Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, and follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.