By Bruce Levine–

(CBS) The thoracic outlet syndrome that has caused a pause in the career of free-agent right-hander Tyson Ross hasn’t curtailed interest from the Cubs.

Ross missed most of 2016 with weakness in his shoulder. His October surgery to relieve pressure from the shoulder to the upper arm was deemed successful, and his recovery time is expected to be four to six months.

The San Diego Padres non-tendered the talented Ross on Dec. 1. Although the Padres love Ross and his makeup, they felt releasing him was more prudent than paying him $10 million for 2017. That’s the salary Ross would have garnered through the arbitration system, regardless if he’s able to pitch.

Ross, who turns 30 in April, was at the top of his game in 2014 and 2015, over which he had a 3.00 ERA in 64 starts. Ross reached the 195-inning threshold each season and averaged 203 strikeouts.

“The Padres would never have non-tendered him if not for the $10 million commitment,” a top National League executive said. “The pitcher will get close to that amount with an incentive-based contract. That is my guess. You need to get a shot at two-year control if you can.”

The Cubs tried to trade for Ross in summer 2015 and again this fall before he was released, a source confirmed. Chicago was offering middle infielder Starlin Castro in late summer 2015. The Padres liked Castro but were more interested in Javier Baez, so the deal crumbled. Talks for Ross were ongoing again up until his release, the source said.

The Cubs have a full five-man rotation in house, with left-hander Mike Mongomery moving up from the bullpen to replace Jason Hammel. Still, that alone won’t give the team the type of depth it will most likely need in 2017. Pitching depth is the No. 1 priority of the Theo Epstein- and Jed Hoyer-led baseball department. With right-handers Jake Arrieta and John Lackey set to be free agents after the 2017 season, there’s an urgency to add pitching now.

The Cubs’ front office is smart enough to know they have been lucky the last two campaigns. The entire rotation missed only four starts by Lackey last season and zero to injury in 2016. A great medical and training staff have been a big part of that success.

But luck isn’t something Epstein and Hoyer want to count in for the future.

“Tyson Ross is a fine young pitcher when he is healthy,” a National League front office member said. “He is an even better person than he is a player. His makeup for me is off the chart. Great teammate, just an all-around, top-quality person.”

The Texas Rangers are also trying to make a deal with Ross’ agent, Joel Wolfe of Wasserman Group. The hope is that Ross will be ready by April to join a rotation. This surgery and recovery is difficult to project, in terms of full recovery and arm strength.

Some have come back fine after such rehab. Others — like Josh Beckett and Chris Carpenter — didn’t. Being younger than those two aforementioned pitchers gives Ross more hope for a complete recovery. Some teams feel he will have a better than even chance of making a full and successful recovery.

Bruce Levine covers the Cubs and White Sox for 670 The Score and CBSChicago.com. Follow him on Twitter @MLBBruceLevine.