The Rangers have signed former Major League left-hander Nate Robertson to a Minor League contract with an invitation to Spring Training. He was signed after a tryout in front of Rangers scout Mike Grouse and Minor League pitching coach Brad Holman.

Robertson, 35, hasn't pitched in the Majors since spending 2010 with the Marlins and Phillies, going 6-8 with a 5.95 ERA in 18 starts and three relief appearances. He was with the Tigers from 2003-09, and has a career record of 57-77 with a 5.01 ERA in 187 starts and 36 relief appearances.

Most of Robertson's time in the Majors has been spent as a starter, but he will likely compete for a spot in the bullpen as a reliever.

Magadan sees Martin's ceiling as 'limitless'

ARLINGTON -- Rangers outfielder Leonys Martin met with new hitting coach Dave Magadan this week at the Ballpark in Arlington. Martin was one of five players who came in to get acquainted with Magadan.

The others were infielders Jurickson Profar and Mike Olt, outfielder Engel Beltre and catcher Jorge Alfaro. All five are among the Rangers' top Minor League position player prospects.

"Today was the last day. I was just acquainting myself with the younger players," Magadan said Wednesday. "We had five guys in here -- a couple guys I've never seen before in person other than video -- so a chance for me to develop a relationship with them, so when Spring Training comes around, we'll hit the ground running and you don't really have to establish that at that point."

Of the five, Martin has the best chance of being with the Rangers on Opening Day. With Josh Hamilton gone, Martin is competing with Craig Gentry to be the center fielder. They will carry that competition into Spring Training, unless the club adds an outfielder from outside the organization.

Michael Bourn is the most prominent free agent who could disrupt those plans. Bourn is considered one of the game's top defensive center fielders and the Rangers have been in contact with his agent, Scott Boras. But there is no indication that a deal is close, and right now, the job appears to be between Martin and Gentry.

"I feel good," Martin said. "I'm sorry that Hamilton went to another team, but I feel great mentally and physically. I feel good about the opportunity."

Martin, who signed with the Rangers after defecting from Cuba two years ago, split time between the Majors and Triple-A Round Rock last season. He played in 24 games for the Rangers and was 8-for-46 with five doubles and two triples. Martin also played in 55 games at Round Rock and hit .359 with a .422 on-base percentage and a .610 slugging percentage. He had 12 home runs and 10 stolen bases in 260 plate appearances.

Martin has been compared to Jacoby Ellsbury, the Red Sox center fielder who flourished with Magadan as his hitting coach in Boston.

"I'd hate to label him and let's let him be what he is, and if he turns out like Jacoby, that'd be nice," Magadan said. "But he doesn't have a lot of experience in pro ball, and the experience that he's gotten, he's done really well. So let's just let him grow at his own pace, and I'd hate to put a label on him and that kind of pressure on him, especially for a guy [from] another country and he's got a lot more things on his plate.

"The ceiling is limitless on him. So we'll let him go at his pace and whatever we can to make him better, and he's definitely a lot like Jacoby in the way he's very coachable, very open. He's got that personality where he's very approachable, those are all good things."

Briefly

• The Rangers are considering the possibility of adding a seventh coach, which is now allowed under new Major League rules. They could opt for the recent trend of adding an assistant hitting coach to work with Dave Magadan.

• Magadan after working with Jurickson Profar this week at the Ballpark in Arlington: "He's as advertised. Always has a smile on his face, just like what I said about Leonys [Martin], very open. Not that I'm coming here changing guys, just little things you say to guys you feel can make them a little more consistent. He's 19 years old, loves being out here. If you let him, he'll hit for two hours in the cage. A lot of energy, a lot of positive energy, and that's a good thing."

• Profar had his winter-ball season in the Dominican Republic cut short by some right forearm soreness, but said the problem has gone away.

"Maybe I was tired," he said. "I rested and now I'm 100 percent."