ARLINGTON -- The Rangers could have a set rotation in place right now if they are content to go into the season with three starters who underwent Tommy John surgery within the past two years.
That's the mystery surrounding Texas with less than a month to go before pitchers and catchers report to Spring Training. The Rangers have five veteran starters in place, but all have undergone significant recent physical issues in their careers.
It would seem unlikely that Texas would go to camp without at least adding more depth.
"We just want to make sure we are covered," general manager Jon Daniels said. "We could add a guy on a guaranteed deal, or guys on a protection [Minor League] deal. We are staying in contact with players in a few different areas. We need to add to the infield, and the bullpen is a concern. We still could add to the starting rotation."
The Rangers had a similar outlook about the group they began the season with last year. Cole Hamels headed a group that included Doug Fister, Martin Perez, Matt Moore and Mike Minor, and they were collectively unable to hold up.
Only Minor made it through a full season for Texas, and its list of starters wound up including Bartolo Colon, Yovani Gallardo and Andrew Hutchison. Overall, Rangers' starters were 43-68, with a 5.37 ERA that was the club's highest since 2008.
Here is where the 2019 rotation stands right now:
Who is returning?
Minor made a successful transition back to starter last season after missing 2015-16 while recovering from a torn labrum in his left shoulder and pitching in relief for the Royals in '17. He was 12-8 with a 4.18 ERA in 28 starts and 157 innings for Texas, including 6-2 with a 2.97 ERA in 10 starts after the All-Star break. He finished with a 1.12 WHIP, the eighth lowest in club history for a minimum of 25 starts and the second lowest in the past 27 seasons.

There was a possibility earlier this offseason the Rangers might trade Minor for young prospects, but that talk has cooled lately.
Edinson Volquez is back for the second season of his two-year contract. Volquez underwent Tommy John surgery on Aug. 4, 2017, while with the Marlins, and Texas signed him in Spring Training of '18 knowing that he would not pitch at all during the season. He is expected to be at full strength when camp opens in February.
Who is new?
The Rangers acquired Drew Smyly from the Cubs in November even though he missed the past two seasons while recovering from Tommy John surgery. He is also expected to be at full strength for Spring Training. Smyly has had to overcome quite a few issues in his career, but from 2012-16, he had a 3.74 ERA and a 1.20 WHIP with the Tigers and Rays while averaging 8.7 strikeouts and 2.5 walks per nine innings.
Shelby Miller had his Tommy John surgery on May 10, 2017, while with the D-backs. He was able to make four starts and one relief appearance for Arizona last year, going 0-4 with a 10.69 ERA. If he is healthy, Texas remembers a pitcher who won 15 games for the Cardinals in '13 and was an All-Star for the Braves in '15.

Lance Lynn, who agreed to a three-year deal with the Rangers in December, missed all of 2016 because of Tommy John surgery, but has made 49 starts and two relief appearances for the Cardinals, Twins and Yankees the past two years. He joins Minor to give Texas two dependable starters at the top of the rotation.
Who could challenge for a spot?
Left-hander Yohander Mendez and right-hander Ariel Jurado had mixed success for Texas this past season. Mendez was 2-2 with a 5.53 ERA and 1.55 WHIP in five starts and three relief appearances for the Rangers, and Jurado was 5-5 with a 5.93 ERA and 1.54 WHIP in eight starts and four relief appearances.
Mendez needs better command of his fastball, while Jurado needs to improve the quality of his secondary pitches. Unless they show dramatic improvement in Spring Training, Texas would prefer they start the season in the Minors.

Who are the dark horses?
Right-handers Jesse Chavez, Rafael Montero and Luke Farrell have been used as starters and relievers at the big league level. So far, the Rangers have preferred to use Chavez out of the bullpen and that appears to be the original intent now. Montero is another Tommy John product who won't be ready for the start of the season. Adrian Sampson isn't overpowering but had a 3.57 ERA and a 1.06 WHIP in four starts at the end of last season.
Who is left in free agency?
Starting with Dallas Keuchel and Giovany Gonzalez, there are enough pitchers left on the free-agent market to build a rotation from scratch. Beyond those two, it's a matter of identifying which pitchers are ready to make a big comeback the way Clay Buchholz did with the D-backs and Wade Miley did for the Brewers last year.
Maybe this is the year to take a flyer on comeback seasons from previously successful Marco Estrada, Thomas Pomeranz or Josh Tomlin. More than one team is going to look really smart by signing the right guy this winter.
Maybe it is Perez. He is only 27 and still available after the Rangers did not pick up his option.

Whoever it is, Texas is sure to add more starting pitching before the market is exhausted.
Who else is in the pipeline? (MLB Pipeline rankings)
No. 3 Cole Winn RHP (age: 19, highest level: Hasn't pitched yet)
No. 4 Hans Crouse, RHP (age: 20, highest level: Class A Hickory)
No. 5 Jonathan Hernandez, RHP (age: 22, highest level: Double-A Frisco)
No. 6 Brock Burke, LHP (age 22, highest level: Double-A Montgomery)
No. 7 Taylor Hearn, LHP (age: 24, highest level: Double-A Frisco)
No. 8 Joe Palumbo, LHP (age 24, highest level: Double-A Frisco)
No. 9 Cole Ragans, LHP (age 21, highest level: Class A Short-Season Spokane)
Projected rotation: (2018 stats)

1. Mike Minor LHP (12-8, 4.18 ERA, 157 IP, 3.7 WAR)
   
2. Lance Lynn RHP (10-10, 4.77 ERA, 156 2/3 IP, 0.9 WAR)
   
3. Drew Smyly LHP (Did not pitch)
   
4. Edinson Volquez RHP (Did not pitch)
   
5. Shelby Miller RHP (0-4, 10.69, 16 IP, - 1.1 WAR)