He may now be 34, but Defoe has shown he has lost none of his goalscoring prowess, having scored 11 times for struggling Sunderland already this season.
Bilic said: "The chairman is trying really hard to get some players, if it's going to be possible, in positions we think we need. I'm not going to talk about names in public.
"(Defoe) has the things that are the most important in a football games - that's goals. He scored them last season, he was probably the main reason they stayed up, and then he continues to do the same this season, scoring again.
"In every game he is having chances and most of the chances he is converting into goals. He is an excellent player, of course."