Ramos was forced out of the 4-0 victory in Belarus on Friday and did not train with the squad on Sunday.
The defender will be back for Monday's final training session before the match at Atletico Madrid's Calderon stadium, Del Bosque told a news conference.
"He told me he was better and we are confident he'll be available for tomorrow," Del Bosque said.
"But if he cannot play we will not force the issue, we won't take risks. In that case someone else will play."
Spain's defence would be considerably weakened without Ramos who, with Real Madrid team-mate Raul Albiol, is one of only two recognised centre backs in the squad.
Tuesday's match could go a long way in deciding who qualifies for the 2014 finals in Brazil as winners of the five-nation group and avoids the play-offs.
While Del Bosque waits on Ramos, he has decisions to make at the other end of Spain's formation, with record scorer David Villa itching for more playing time as he continues his recovery from a broken leg.
"I need to be patient but I am ready to play already," he said at a book presentation at Spain's training camp outside Madrid on Monday.
"I know my leg will respond, I am not so sure about my stamina," added 30-year-old Barcelona forward Villa.
"I found it really hard to smile these past months but my friends and family helped me through it and I will thank them for the rest of my life. Now I am happy and I smile more."
