Christian football star Tim Tebow has had a rough time finding success in the National Football League (NFL), and country singer Blake Shelton just cannot understand why no team has signed him on despite his talent.

"Just saw the 2011 playoff game with Steelers vs. Broncos. Can someone please give me a good reason (why) Tim Tebow isn't playing in the NFL," Shelton said on Twitter. "I mean are you telling me that there's NOT a team that needs him out there? Look at the problems so many teams have at quarterback!"

One fan responded by saying, "I know right?? I mean he's at least as good as half the NFL QB's." Shelton enthusiastically responded, "Exactly!!!!! My God he's won a playoff game!!!!!!!!! How many QBs in this league can even say that?!!"

When one netizen weighed in that Tebow might have been overlooked "because he is religious," Shelton was disheartened. "Is that seriously the reason?!! (Expletive!!) That's pretty sad.. Glad they don't hold country singers to that standard."

Some did not agree with Shelton about Tebow's athletic prowess, with one saying, "He's no good Blake."

Shelton was relentless in his defence of Tebow. "But he's so much better than a lot of starters!!! You can't argue that!!!! Come on!!!"

Last year, Tebow had a brief stint with the Philadelphia Eagles. He got into a one-year contract with them on April 20, 2015, but was subsequently released on September 5.

Coach Chip Kelly recognised Tebow's dedication and progress, but said the athlete needed to improve some more. "Tim's really progressed but we didn't feel like he was good enough to be the three right now," he said, according to CBS Sports. "He just needs to get out there and get more reps."