Two new ballparks debut in New York tonight, with the Cubs making the first appearance as the visiting team at the new Yankee Stadium and the Mets hosting the Red Sox at Citi Field. Opening Day is just around the corner, and the new digs will be home to two of the game’s premier closers.

Former Angel Francisco Rodriguez will debut a new uniform for Citi Field’s initiation on Friday. He joined the Mets after setting the single-season record with 62 saves last season. The Yankees, of course, have Mariano Rivera, who ranks second all time in saves behind Trevor Hoffman with 482. The 39-year-old Rivera was as dominant as ever in 2008, saving 40 games and posting a 1.40 ERA.

Not all saves are alike, however, as there’s a big difference protecting a one-run lead compared to a three-run margin. In light of Rodriguez’s record-setting save total last season, it’s not exactly surprising that he also posted a major league high of 23 one-run saves. Next on the leader board were Rivera and Minnesota’s Joe Nathan, both with 17.

Rivera converted all 17 of his one-run save opportunities. Among closers with at least 10 one-run save chances, Rivera was one of only two who were perfect in those situations. Philadelphia closer Brad Lidge was the other.

Highest Save Percentage in One-Run Save Opportunities, 2008
(min 10 one-run save opportunities)

. . . . . . . . . . . . . . . . . . . . . Sv/Opp. . . . Pct
Mariano Rivera, NYY. . . . . . . .17/17. . . . 100.0
Brad Lidge, Phi. . . . . . . . . . . 16/16. . . . 100.0
B.J. Ryan, Tor. . . . . . . . . . . .13/14. . . . . 92.9
Bobby Jenks, CWS. . . . . . . . . 11/12. . . . .91.7
Francisco Rodriguez, LAA. . . . 23/27. . . . .85.2
Brian Wilson, SF. . . . . . . . . . .16/19. . . . .84.2

Surprisingly, Toronto’s B.J. Ryan has struggled all spring. Reportedly his velocity is down in the mid-80s, and the 33-year-old left-hander has been working on mechanical tweaks to boost his radar readings. This comes after Ryan made a strong return from Tommy John surgery in 2008.