SAN DIEGO -- Like 29 other teams, the Padres would love to add some starting pitching before Spring Training begins.

"It's as wide open as you could imagine a Major League rotation being," Padres manager Andy Green said last month.

But the rotation race -- which once seemed impossible to decipher -- has received a bit of clarity over the past few weeks. With Clayton Richard , Jhoulys Chacin and Tyrell Jenkins on board, the Padres now appear to have eight pitchers fighting for five spots. (We'll say eight, because barring something unexpected, prospects Dinelson Lamet and Walker Lockett will start the season at Triple-A.)

There's still plenty of time until the April 3 opener at Dodger Stadium. But the "wide-open" race for starting jobs finally has a shape. Here's a breakdown of the candidates:

RICHARD

His case: Richard was very sharp in his return to the Padres last season, posting a 2.52 ERA over 11 appearances. He clearly loves pitching in San Diego, and his ground-ball rate over the final two months was the highest among starters.

Left to prove: His solid finish was only a small sample, and the Padres will be asking him to eat some serious innings this year. Plus, Richard's peripherals -- namely a 1.53 WHIP and a 4.19 FIP -- don't bode well.

Early verdict: The Padres re-signed Richard to be a veteran leader on a young pitching staff. It's hard to envision a scenario in which a healthy Richard doesn't make the rotation.

LUIS PERDOMO

His case: Perdomo's second half is likely all the case he needs for a starting job in 2017. Once he got a feel for his sinker -- still a very new pitch -- Perdomo became the Padres' most effective starter.

Left to prove: Perdomo's sinker is undoubtedly a weapon. But the Padres would like to see the 23-year-old sophomore turn his breaking ball into a complementary out pitch. Plus, Perdomo needs to hone his command a bit to take the next step.

Early verdict: Unless Perdomo completely loses the feel for his sinker, he'll be back in the rotation. (But don't be surprised if the Padres send the youngster to Triple-A for a midseason breather, as they did with Colin Rea last year.)

CHACIN

His case: Upon his arrival in Anaheim last season, Chacin found a bit of a rhythm -- despite his poor ERA. For the most part, he kept the ball on the ground, and he could benefit from pitching at Petco Park.

Left to prove: It's been four long years since Chacin posted a 3.47 ERA and a 5.8 WAR on the 2013 Rockies. The Padres believe he can recapture that form, but his numbers from the past three seasons aren't pretty.

Early verdict: Chacin signed largely because the Padres offered him a chance to start. Barring a poor Spring Training, he'll get that opportunity.

CHRISTIAN FRIEDRICH

His case: In his first six starts with the Padres, Friedrich posted a 2.12 ERA before coming undone in July and August. Although he wasn't sharp late in the season, Friedrich was reliable for five to seven innings.

Left to prove: There's not a whole lot for Friedrich to prove before the opener. But as the season progresses, he'll need to show he can sustain the grind.

Early verdict: Friedrich has the inside track to a rotation spot, after leading the Friars in starts in 2016. But there's work to be done if he wants to maintain it.

JARRED COSART

His case: Upon his arrival at the non-waiver Trade Deadline, Cosart allowed one earned run or fewer in four of his first five starts, consistently limiting hard contact. In September, that changed quickly. The goal will be to harness his August success.

Left to prove: Prone to the big inning, Cosart needs to work on his mound presence. Too frequently in 2016, the right-hander let one mistake spiral into several more.

Early verdict: Cosart underwent minor surgery on his right elbow this offseason, but he should be fully healthy by Opening Day. If that's the case, Cosart is squarely in the mix for the No. 5 spot.

PAUL CLEMENS

His case: Green challenged Clemens to earn a starting job after a string of early exits last season. How did Clemens respond? By allowing two earned runs over his final four starts.

Left to prove: After joining the Padres in early July, Clemens never threw more than 87 pitches in a start. That's not ideal for a staff in dire need of innings-eaters.

Early verdict: The Padres remain high on Clemens' fastball/curveball mix. But it's unclear whether he can sustain success as a starter without another weapon.

CESAR VARGAS

His case: Before he suffered an elbow injury in Arizona last May, Vargas became the second Padre in history to allow one run or fewer in each of his first three career starts. His cutter is a legitimate Major League out pitch.

Left to prove: Everything. Vargas' first stint in the big leagues was far too short to gauge anything -- other than the fact that he has the calm temperament necessary to start in the Majors.

Early verdict: If he's the same pitcher who posted a 3.34 ERA before that fateful outing at Chase Field, Vargas will have a great shot at a rotation job. But there's no telling how his elbow will respond. (He made 10 relief appearances in the Mexican Winter League and posted a 1.98 ERA.)

JENKINS

His case: The 24-year-old right-hander made his debut last season for Atlanta. And though he struggled, he clearly hasn't reached his fullest potential. Jenkins will get a chance to show off his development in camp.

Left to prove: Jenkins has never been one to miss many bats, and that's a serious problem at the big league level. His rate of 26 strikeouts to 33 walks last season was abysmal.

Early verdict: As it stands, Jenkins is probably on the outside looking in. But he has plenty to pitch for this spring. If any of the above hurlers get injured or struggle, Jenkins might be the next man up.

AJ Cassavell covers the Padres for MLB.com. Follow him on Twitter @ajcassavell.