On the mend, UFC champ Anthony Pettis trades barbs with Nate Diaz

Although they never officially addressed each other, UFC lightweight champion Anthony Pettis and former title challenger Nate Diaz apparently are, in the parlance of the latter, beefin’.

Pettis, who recently pulled out a planned UFC on FOX 9 headliner with Josh Thomson, is on the mend following a knee injury he originally suffered in his title-clinching win over then-champ Benson Henderson. The injury, a torn posterior cruciate ligament (PCL), could keep the champ out of action for up to year, and surgery reportedly hasn’t been ruled out.

Never one to bite his tongue, Diaz seemingly gave the champ a kick while he’s down in a Monday tweet.

Bitching outta everyother fight now ?wonder what that’s like? #urpayingthesepussys

— Nathan Diaz (@NateDiaz209) November 11, 2013

Whether or not it was directed at Pettis, the usually mild-mannered titleholder issued a response to Diaz, who looks to end a two-fight losing skid when he meets Gray Maynard later this month in the headliner of The Ultimate Fighter 18 Finale. Pettis didn’t mention Diaz by name, but it’s not too difficult to read between the lines of Wednesday’s tweet.

2 losses + lisssssp + best offense is your middle finger = can’t talk shit!!! #votepettis

— Anthony Pettis (@Showtimepettis) November 13, 2013

Later, Pettis seemed to regret the tweet.

I shouldn’t let people who talk trash get me out of character. #champ4areason

— Anthony Pettis (@Showtimepettis) November 14, 2013

For now, Pettis (17-2 MMA, 4-1 UFC) is Las Vegas for this weekend’s UFC 167 event, where little brother Sergio makes his promotional debut as the youngest fighter on the UFC’s current roster.

Diaz (16-9 MMA, 11-7 UFC), meanwhile, is wrapping up his camp for his Nov. 30 rematch with Maynard (11-2-1 MMA, 9-2-1 UFC). Diaz submitted Maynard on “The Ultimate Fighter 5? but suffered a split-decision loss to “The Bully” in an official bout in 2011.

For more on the TUF 18 Finale, stay tuned to the UFC Rumors section of the site.