ALAMEDA, Calif. — The Oakland Raiders found the replacement for disappointing former first-round pick Rolando McClain, agreeing to a free-agent contract on Friday with former Chicago linebacker Nick Roach. Roach’s agent, Josh Wright, confirmed the two sides agreed to the deal. Roach is the second linebacker signed by Oakland this week, following a three-year, $6 million deal given to Kaluka Maiava on Wednesday. Maiava is expected to replace Philip Wheeler, who left to sign a five-year, $26 million deal with Miami earlier this week. The deal with Roach fills the hole in the middle created by McClain’s disappointing play. McClain, …