Cleveland Indians ace Corey Kluber has spent his career proving doubters wrong. So, why should this season be any different?

First, he had to prove that he could be a consistently effective Major League pitcher. Tabbed as a fourth round draft pick in 2007 by the San Diego Padres, Kluber was merely decent, at best, in their minor league system and then in the Tribe’s farm system after his 2010 trade to Cleveland.

When the Padres traded Kluber three years after drafting him, he had to prove to the Indians that he was worth receiving in a three-team deal that saw the Tribe send dependable veteran starter Jake Westbrook to St. Louis.

Once Kluber finally did break through to the Majors, there were doubts about just how good he could be. Initially, it was wondered if he could be any more than a back of the rotation pitcher and then, certainly, he would never be more than middle of the rotation.

When he went 11-5 with a 3.85 ERA during Cleveland’s 2013 Wild Card campaign, many thought that was about where his peak lie. It was not bad for a guy who had a 3.59 ERA in 21 Triple-A starts the year before. While pretty good – those minor league numbers did not exactly scream of a guy who could be the number one starter of a MLB pitching staff.

Then, Kluber really started to prove the doubters wrong. In 2014, he showed he could not only pitch consistently well in the big leagues, but that he could be as good as anyone in the game. He went 18-9, with a 2.44 ERA en route to winning the American League Cy Young Award. Still, some thought that he may have had one of the out-of-nowhere seasons and he would go back to being a number three pitcher in 2015.

He proved he was no fluke, following up his Cy campaign with a solid year after. Despite a subpar 9-16 record in 2015, he still finished ninth in that season’s Cy balloting. The victim of poor run support, the Klubot still struck out 245 batters, had a solid 3.49 ERA, and toted an impressive 1.05 WHIP. He was nearly as good that year as he was in his award-winning season, despite the record.

Still, there were doubts as to whether he could carry a rotation and be a consistent winning pitcher. In 2016, he matched his 2014 record of 18-9 and had a strong 3.14 ERA. He was the unquestioned ace of an Indians team that won the AL Central Division and got to within one run of winning its first World Series since 1948. He finished third in last year’s Cy Young voting, though many thought he deserved to win his second piece of hardware.

To those who wondered what kind of big game pitcher Kluber could be, he answered that in a resounding way. Kluber simply carried the Indians in the 2016 postseason until he flat out ran out of gas in Game 7 of the Fall Classic. He pitched on short rest once in the ALCS and twice in the World Series. He started six postseason games, going 4-1 with an eye-popping 1.83 ERA in 34 1/3 innings. The Indians would not have gotten anywhere near as close to winning the Commissioner’s Trophy without his postseason heroics. That is especially so considering two starters – Danny Salazar and Carlos Carrasco – were out of the postseason rotation with injuries and a third, Trevor Bauer, chopped up his pinkie before the start of the ALCS in a self-induced, drone-related accident.

After three excellent seasons and a postseason for the ages, Kluber is certainly among the game’s elite starting pitchers. He has proven to be among the best in all of baseball, except now there are some around the game questioning if he can be as effective this year, at least out of the gates, as he has been in season’s past.

Some think Kluber’s heavy postseason workload of last October could catch up with him and see him struggle more than normal this year. After being eased into spring training games slowly, is he ready to start the season? Will his arm be rubber after last season or can it bounce back quickly and have its normal life and velocity? Can he maintain that level of excellence that has made him a Cy Young contender two of the last three years?

Kluber will get a chance to answer those questions pretty quickly. Right away, in fact. He starts Game 1 of the regular season Monday night in Arlington, Texas. He will face off against Rangers ace Yu Darvish. We will know, out of the chute, if Kluber really is a robot like some may want to think.

If Kluber can carry a team through the postseason grind and then be able to pitch at an ace-like level on Day 1 of the regular season, there should never be any doubts about him again.

Cleveland’s number one hurler has looked every other doubt in the face and shoved it aside, kicking the door in on one of the better, more memorable careers for an Cleveland Indians pitcher since the great Bob Feller.

Could he make it as a dependable big league pitcher? Could he be anything more than a middle-of-the-road starter? Could he be a Cy-Young caliber pitcher more than one season? Could he lead a team to the postseason? Could he maintain a magnificent level on baseball’s great October stage? He has answered a truly Major League yes to all of those.

Now a good question in all of that may just be why he can’t continue to be terrific even after so many October innings. He has been the true definition of a workhorse the last four seasons. He has rarely missed a start and been consistently great.

Also in Kluber’s favor is a manager in Terry Francona that has seen and done it all in the game. This will be the third time Tito has managed a team a season following a World Series trip. He knows how to handle the rigors that the prior year brought and continue to have success the next year. Both season’s following World Series championships when he was with the Red Sox ended with 95 wins and trips back to the playoffs. Francona knows how to manage high expectations and players coming off of longer than normal campaigns.

Kluber has proven over the last few years that he is as good as anyone in baseball. It seems silly to question whether or not he can stay at the great level he was at. Instead, we should be wondering how good again he can be. We should be thankful that the player who will turn 31 in eight days, is under contractual control of the Indians through the 2021 campaign, when he will be 35.

There should be no doubting the Klubot at this point and only wondering just how good he can be. Maybe this year he can go to a second straight All-Star Game. Maybe he can win a second Cy Young Award. Perhaps there will be a first in that he can help lead the Tribe to its first World title in 69 years. Now that would be a truly crowning achievement for a guy who has already done everything else the last three years.

Photo: Elsa/Getty Images