Cubs manager Joe Maddon said Friday ''he is just going through a little bit of a dead-arm period.''
Lester, who signed a $155 million, six-year contract during the offseason, is not experiencing pain, according to Maddon, and has gone through similar periods in previous spring trainings.
''More than likely, he will not miss the start after that,'' Maddon said. ''But we wanted to be very cautious with it right now. And at this point it does not impact opening day. I really feel strongly that he's going to be OK.''
Erick Jokisch will start in Lester's place Saturday against Seattle in Mesa.