Why rely on Park?
But it's not all that hard to remember when Perez was not awful. In 2004, he finished No. 1 in the National League in strikeouts (239) and No. 6 in ERA ( 2.98). With Perez, it's not hard to dream a little, and baseball men do love to dream. (What's more -- though of course it's still quite early -- to this point Perez is pitching something like a dream.)
Chan Ho Park, though? After Park signed a huge, five-year contract following the 2001 season, his ERAs went like this: 5.75, 7.58, 5.46, 5.74, 4.81. That 4.81 came last season with the Padres, who happen to play in the pitcher-friendliest ballpark in the major leagues. His ERA away from that pitcher-friendliest ballpark last season: 5.45. So leaving aside that 7.58 mark in 2003 -- he was hurt that season, and started only seven games in the majors -- Park seems to have established a fairly consistent level of "ability."