Eliezer seems like a minor figure in the bible, but he was actually a very important member of Abraham's household.

Eliezer was going to be Abraham's heir until he had his sons.

Eliezer was most likely the servant who went on a mission to find a wife for Isaac and came back with Rebecca.

Eliezer was probably the head of the war party who go to rescue Lot.

"And when Abram heard that his brother was taken captive, he armed his trained servants, born in his own house, three hundred and eighteen" Genesis 14:14

It didn't mention Eliezer's name here, but it mentions his number. 

Aleph א 1

Lamed ל 30

Yod י 10

Ayin ע 70

Zayin ז 7

Resh ר 200

Total א+ל+י+ע+ז+ר 318

The 318 was a nod to Eliezer who led the war party.