Infielder Rico Washington was optioned to Triple-A Memphis to make room for Springer on the roster, leaving the Cardinals with 13 pitchers and 12 hitters.
Initially, the club had hoped to give Springer one or two more simulated-game sessions before adding him to the roster. However, with three relievers unavailable Monday, and at least two of them still on the shelf for Tuesday, the decision was made to activate Springer.
Anthony Reyes and Ron Villone each pitched three innings on Sunday, making them off limits until at least Wednesday. Brad Thompson threw 2 2/3 innings on Saturday, so he will not be available before Tuesday, at the earliest.
"If you look at the number of pitches those guys threw, we just felt like we needed some protection in case we find ourselves in that scenario again," general manager John Mozeliak said on Monday. "The crux of it was, if we would have had Springer throw that simulated game today, then we wouldn't have him available."
The Cardinals, thus, elected to defer a decision on which hurler to trim from the roster -- at least for a few days. Thompson, Reyes and Kyle McClellan, who all have options, will remain with the club. It's likely a pitcher will be sent down when infielder Brendan Ryan is activated from the disabled list, which could come in a few days.
Ryan has not played a game this season. He sustained a rib cage injury -- specifically, an intercostal muscle strain -- on March 17. The infielder began his Minor League rehab assignment on April 13.
"His last game was on the 17th of March," Mozeliak said. "He would have ultimately played almost every day, getting three or four at-bats, leading up to Opening Day. He didn't get that. So we have to replicate that, and we're doing that in the form of a rehab."
Washington was one of the early season's best stories, making the club out of Spring Training after nearly 4,000 career Minor League at-bats. He struggled at the plate, though, going 3-for-19 with a .273 on-base percentage and a .263 slugging percentage in his brief stint with the Major League team.
The decision would seem to indicate that Reyes will not be the odd man out when the next decision comes. Reyes threw three innings of relief on Sunday, so if the club had wanted to send him down, Monday would have been the perfect time. He will not be available for at least a couple of days as it is.
Cardinals manager Tony La Russa, meanwhile, has expressed an extreme reluctance to part with McClellan, who has pitched effectively in several high-pressure situations.
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.