Charlie Sheen as Charlie Goodson, Selma Blair as Kate Wales on “Anger Management.” (Adam Rose/FX)

FX telecasts the final episode on its initial 10-episode order of Charlie Sheen’s comedy “Anger Management” tonight, after which the network will announce whether the show hit the ratings threshold under which the network is obligated to order 90 additional episodes, per its contract with Lionsgate, which produces the show.

Last month, FX programming chief John Landgraf said episodes 2,4,5, and 6 had exceeded the ratings threshold that’s required for the “back 90” renewal. The first two episodes, which ran back to back on premiere night, were excluded from the formula, which governs that pickup agreement, he told TV critics at Summer TV Press Tour 2012.

That’s a pity for Sheen and the producers because those first two episodes clocked an average of 5.5 million and 5.7 million viewers, making it the most watched scripted primetime comedy series premiere in cable history at that time — excluding children’s programming. It was also the most watched series premire, drama or comedy, in FX history. It was much the same story among the 18-49 year olds who are the currency of FX ad sales.

Since Landgraf made that statement, the ratings for episodes 7,8, and 9 have all come in smaller than that earlier batch, though for more recent weeks, the stats for DVR viewing up to seven days after premiere — which is industry standard these days — are not yet available.

Over the course of its run, “Anger Management” has averaged more than 4 million viewers, more than 2 million of whom are 18-49 year olds.

At his press tour Q&A session, Landgraf said he would not make a decision on the 90-episode pickup until all 10 episodes have aired. But, he added, that “in the very likely event that those 90 episodes….are produced,” Martin Sheen would join the cast, playing Charlie Sheen’s character’s dad. Martin Sheen would have a recurring role on the show, which means he would appear in several, but not all, of the 90 episodes.