ST. LOUIS -- When the Cardinals picked up Mark DeRosa from Cleveland in June, one of the first questions for general manager John Mozeliak was, essentially, "What's next?" Now we know.

It will be all but impossible to top the trade for Matt Holliday on Friday, a move that stands as the biggest trade in baseball since the 2009 season started. That doesn't mean the Cardinals are entirely done, however. They still have a couple of holes that could be plugged, but any additional acquisitions will be of the peripheral variety, rather than earth-shakers.

St. Louis would still benefit from a right-handed reliever to help with setup duties, and a fifth starting pitcher would help, as well. But it's very clear that Blue Jays ace Roy Halladay is off the table as far as the Cardinals are concerned. If St. Louis picks up a starter, it would be a back-of-the-rotation type, rather than an ace.

The bigger question, actually, may relate to what happens after the season ends. Holliday is a free agent at the end of the year, and the Cardinals gave up three prospects to get him. They would likely receive two Draft picks if he leaves as a free agent, but the preference would be to retain the services of a player whom St. Louis so long coveted.

The Cardinals did not receive a three-day negotiating window to broker a new deal with Holliday, though that privilege is sometimes granted when a player is traded.

"Obviously in a deal at this level, you contemplate everything," Mozeliak said. "But with where we were in the season, the timing of it, we just really thought that would complicate matters. So to get to where we are today, we just decided that we would explore it later in time and just add him to our club and give him the opportunity to start playing right away."

Mozeliak did not rule out negotiating with Holliday before the season ends. The Cardinals have used that tactic before, re-signing Scott Rolen, Jim Edmonds and Mark McGwire after picking them up in trades.

"I'm obviously going to be open to something," Mozeliak said. "But right now let's just let him fit in and join the club and get a taste of St. Louis when he gets back there."

Complicating matters is that Holliday is represented by Scott Boras, an agent with a long history of taking his clients to free agency whenever possible. However, Boras did agree to a new deal for client Kyle Lohse last season before Lohse hit the open market.

For his part, Holliday danced around a question about his future beyond this season.

"I'm pretty sure that I'm excited to be a St. Louis Cardinal, and I'm ready to go out on the field and hit," he said.