​While extensions have recently taken over the game, count one of its most consistent stars out for now.

According to MLB insider Jon Heyman, Anthony Rendon and the Nationals have spoken regarding an extension, but are nowhere close to an agreement by Opening Day. 

No need to mince words: Rendon, who seems to be getting better by the year, is a player the Nats have got to lock up, given their loss of phenom Bryce Harper and the lack of available third base talent next offseason and beyond.

Rendon, who was drafted by the Nats sixth overall in 2011, has been an ​underrated star since being called up in 2013. Over his six-year career in the bigs, Rendon has had a .285 batting average while knocking in 420 runs, despite his poor health restricting the majority of his 2015 season. 

After losing Harper, ​the Nationals have to do everything in their power to keep key offensive pieces, and it would be better to do so sooner rather than later. If the Nationals are able to lock up Rendon at some point during the season, they will be able to relax a bit, knowing that their current best hitter will be with the team for the near future. In addition, with two of the best third basemen in the league being locked up on massive contracts now (Machado, Arenado), there will be a huge market for a third basemen of Rendon's caliber and age for needy teams. Washington can't let it get that far. 

This is not to mention, of course, that as devastating as it was to lose Harper, Washington has superman Juan Soto ready to develop as their next outfield star, with hot prospect Victor Robles directly inhabiting his shoes. Not quite as disastrous as losing a third baseman like Rendon, after all.

At age 29, Rendon remains in his prime, meaning that we will likely see even more production from the 6-1 righty in the three years to come. Mike Rizzo and the Nationals brass are going to have to lock him up now, before he hears a slew of tempting offers on the free agent market.