K-Rod: 1 IP, 1 H, 0 R, 1 BB, 2 K (SV)
Seattle was Francisco Rodriguez’ victim as he broke the all-time single season record for saves.
While I do, check out Baseball-Reference’s Progressive Leaders for saves (the answer’s there). B-R’s Progressive Leaders board is fun to look at for any stat. It lists 4 columns for EACH year going back to 1876; career leader, single-season leader, active player career leader, and yearly leader. It sounds rather mundane as I describe it but when you look at all four columns together, you get a sense of how the stat (in this case, saves) "progressed". Try other stats, too!
Oh, the answer is Dave Righetti with 46 saves in 1986.