NFL quarterback Tarvaris Jackson is playing defense for a change ... pleading not guilty to allegations he pulled a gun and threatened to shoot his wife during a domestic incident last month.
33-year-old Jackson was charged with aggravated assault with a deadly weapon after he allegedly pointed a loaded gun at his wife during a fight in Florida on June 24th.
As we previously reported, the former QB -- who played in the NFL for 9 years -- was denied a free public defender even though he said he didn't have the funds to hire an attorney.
Looks like he found a lawyer after all ... 'cause according to court docs, an attorney entered a not guilty plea on his behalf on Friday.
If convicted, Jackson faces up to 5 years in prison.