In addition, the Cardinals agreed that if Penny is a Type A free agent after the 2010 season, they will not offer him arbitration.
General manager John Mozeliak said that a Penny signing would not necessarily complicate the team's attempts to re-sign outfielder Matt Holliday.
"It's a reflection of what we've stated all along, that we're looking to sign a starting pitcher," Mozeliak said. "Short-term is something that we're interested in. In terms of [whether we can] still do more, the answer is yes."
Penny bolsters a St. Louis rotation that has the potential to be one of the league's best once again. He joins 2009 Cy Young candidates Adam Wainwright and Chris Carpenter, as well as veteran Kyle Lohse, in the Cardinals' starting five. The last spot is, as of now, likely to go to a pitcher from within the organization, with Jaime Garcia as the leading candidate.
However, Mozeliak acknowledged on Monday that that plan is no longer as certain as it once seemed. He left the door open to an additional pitching pickup, in the event that Holliday does not re-sign with the Cardinals.
For Penny, the deal represents something of a make-good opportunity, a chance to follow up a late-2009 resurgence. Penny, who will turn 32 next season, saw his career rebound dramatically after nearly two seasons of struggles when he returned to the National League this summer.
Health issues contributed to a subpar 2008 with the Dodgers, and Penny struggled in four months with the Red Sox. But after Boston released him, Penny signed with the Giants and thrived, going 4-1 with a 2.59 ERA in six starts. He likely benefited from getting out of the American League East, but he also showed a new approach, with a greater willingness to turn to offspeed offerings.
As a result, he not only pitched effectively, but differently. Penny struck out fewer batters with the Giants than usual, but he also walked fewer and induced more ground balls. That's the sort of pattern that appeals to the Cardinals, who hold an organizational belief in the value of quick outs and letting the defense work.
As recently as 2007, Penny was one of the game's best starting pitchers. He went 16-4 with a 3.03 ERA for Los Angeles in '07, allowing nine home runs all season while garnering an All-Star berth and finishing third in the Cy Young balloting. For his career, he's 105-84 with a 4.14 ERA, 1,141 strikeouts and 526 walks in 279 games with the Marlins, Dodgers, Red Sox and Giants.
Penny remains among baseball's hardest-throwing starting pitchers. He features a four-seam fastball, which averaged 94 mph in 2009, as well as a curveball, and has at times mixed in a slider and a changeup.
Despite something of a checkered health history for Penny, Mozeliak did not indicate any urgency on the club's part to add a buffer pitcher to protect a potential breakdown by the new addition.
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.