© 2014 MLB Advanced Media, L.P. All rights reserved.

8/27/2014 1:39 A.M. ET

Story among four Rox prospects going to AFL

DENVER -- The Colorado Rockies assigned four position players to the Arizona Fall League on Tuesday. But with some of their Minor League affiliates still having a slate of playoff games to go, the Rockies held off on selecting any pitchers.

Double-A Tulsa catcher/first baseman Ryan Casteel, shortstop Trevor Story and middle infielder Taylor Featherston each were included on the 35-man roster of the AFL's Salt River Rafters. Catcher Chris O'Dowd, son of Rockies general manager Dan O'Dowd, was also chosen as the "taxi squad" member of the roster, meaning he's only active Wednesdays and Saturdays.

With Double-A Tulsa winning its division in the first half of the Texas League, Class A Ashville clinching a playoff spot and the Rookie-level Grand Junction Rockies also looking likely for the postseason, the Rockies will wait on naming their four pitchers.

If their workloads permit, right-hander Jon Gray, left-hander Tyler Anderson and right-hander Eddie Butler could all be options out of Double-A Tulsa.

The Rockies originally had Anderson on their AFL roster last season before pulling him out after discovering a stress fracture in his throwing arm. Butler made his Major League debut with the Rockies earlier this season but they could be looking for him to make up lost time after he missed over a month with right shoulder inflammation.

As for the players that have been decided, Story, the Rockies' No. 11 ranked prospect, is the most notable selection.

The 21-year-old has struggled since his promotion earlier this season and is batting .200 (37-for-185) with 74 strikeouts at the Double-A level. The Rockies will be hoping to see something closer to the .332 average and 17 doubles he posted for Class A Advanced Modesto through 50 games to begin the season.

Casteel has spent his entire season in Double-A, batting .274 (113-for-413) with 21 doubles, 16 homers and 56 RBIs.

Featherston has put up similar powers numbers at the same level this year with 31 doubles and 16 homers to go along with his .257 (121-for-471) batting average.

After beginning the season with Modesto, O'Dowd has hit .261 (30-for-115) with six doubles and 15 RBIs in 33 games with Tulsa this season.

Tulsa manager Kevin Riggs will also be acting as the hitting coach for the Rafters for this upcoming AFL season.

De La Rosa's start ends with thumb injury

SAN FRANCISCO -- Colorado starter Jorge De La Rosa left Tuesday night's 3-0 loss to the Giants in the bottom of the sixth inning with a left thumb contusion after giving up a two-run homer to catcher Buster Posey.

With one on and none out, Posey broke up a scoreless tie by depositing one into the left-field bleachers. Shortly after Posey finished rounding the bases, Rockies manager Walt Weiss and a team athletic trainer went out to the mound to speak with De La Rosa, who walked back to the dugout after a short consultation.

De La Rosa was seen shaking his hand after fouling off a pitch during his sixth inning at-bat.

"My thumb was really, really numb," De La Rosa said. "I don't like to make excuses, but you can't pitch with that thing. I made that mistake for Posey and paid for it."

De La Rosa said it's similar to the thumb pain that caused him to miss the final two weeks of the 2013 season, but that he will "for sure" make his next scheduled start Sunday against the D-backs.

"He's pitched with it a lot, but I think it was hurting pretty good this time," Weiss said. "I don't have any major concerns right now. We've seen this before with Jorge with his thumb. Hopefully it's just a bruised thumb again and he'll be fine."

De La Rosa was in the midst of a quality start, but the Rockies were being held scoreless by San Francisco lefty Madison Bumgarner, who completed a one-hitter. Right-handed reliever Matt Belisle was summoned from the bench to take over for De La Rosa.

Ailing wrist could land Rosario on disabled list

SAN FRANCISCO -- The crowded Colorado disabled list could be adding another member in the near future. Before Tuesday night's contest against the Giants, Rockies manager Walt Weiss hinted that catcher Wilin Rosario's bothersome left wrist might keep him out longer than expected.

"He's been getting treatment and trying to swing the bat in the cage the past couple days," Weiss said. "But he's getting close to probably looking at a DL [stint] is what we're looking at. The wrist just isn't responding like we want."

Rosario has been out since Friday while Michael McKenry made his fourth straight start behind the plate Tuesday. Other top sluggers like Carlos Gonzalez, Troy Tulowitzki and Michael Cuddyer are currently on the disabled list for Colorado.

Outfielder Matt McBride has limited previous experience as a catcher in the Minor Leagues and the rosters are set to expand to 40 men Monday, but Weiss said the team would promote a catcher if Rosario lands on the 15-day disabled list.

"It's just too long to go without one," Weiss said. "But Matt can go back there and catch obviously. He hasn't done it during the season. He did it a lot during Spring Training for us, but we'd have to bring a guy in."

The only other catcher listed on Colorado's 40-man roster is Jackson Williams. The 28-year-old, who has never appeared in the big leagues, is currently batting .256/.353/.368 with four homers and 34 RBIs in 72 contests with Triple-A Colorado Springs.

Rockies shining at getting double plays

SAN FRANCISCO -- When it comes to turning two, there's been no better team in baseball than the Rockies.

The team's stellar defense was on display in Monday night's 3-2 win over the Giants, as Colorado matched its season high by turning four double plays to bring its total to a Major League-best 138.

"Any time a pitcher can make a pitch and get you a double play, it gives the team momentum and puts you in a good spot even if it's only two outs," shortstop Josh Rutledge said. "It's great that pitchers get rewarded for making a good pitch. That's one of the big things we've been working on since Spring Training because it gives you a certain level of comfort no matter who's there. I feel like we work on that as much as we do ground balls. It's paid off."

Manager Walt Weiss, who was a fine defensive shortstop during his 14-year playing career, attributed much of the team's defensive success to the work of third-base coach Stu Cole. Following Monday's victory, Weiss also praised the pitching staff for its ability to induce ground balls when needed.

But the statistic also speaks to the team's infield defense, especially on the left side. Reigning Gold Glover Nolan Arenado ranks first among National League third basemen in double plays (30) despite missing about six weeks due to injury, while Rutledge has filled in nicely for Troy Tulowitzki since he went out for the year.

"I think he's looking a lot more comfortable defensively," Weiss said of Rutledge. "He looks smooth to me out there right now. He's going left to right, finishing plays. It looks like there's a level of comfort right now that we're seeing that maybe it took him a little bit of time to get there."

Morneau in rare company for Canadians

SAN FRANCISCO -- With a pair of singles in Monday night's 3-2 victory over the Giants, Justin Morneau jumped into second place on the all-time hits list for Canadian-born players.

The veteran first baseman entered play Tuesday with 1,468 career hits, one more than 19th-century ballplayer George Wood. But even after adding a double in Tuesday's 3-0 loss to the Giants, he still needs 691 more hits to match the all-time leader and former Rockies great Larry Walker.

"Any time you're second to him in anything, it's special," Morneau said. "Especially being a Canadian guy that I looked up to as a young guy. It's pretty cool, but I've got a long way to go."

So as Morneau was developing as a prep player and Walker was forging his career that included a 1997 MVP Award, Morneau identified with Walker closely. Morneau always had respect for other Canadians like Hall of Fame pitcher Fergie Jenkins, but then there was Walker, another left-handed slugger from British Columbia.

"He was the guy for us growing up who really let us know that we could play in the big leagues, and let us know we can do well," Morneau said.

The Canadian duo has formed a relationship over the years. Walker used to send Morneau bats and has coached him in the World Baseball Classic, and the two share an agent. Morneau also fondly remembers making his Major League debut in 2003 against Walker and the Rockies.

It's no coincidence that Morneau has worn the No. 33 since his high school baseball and hockey days.

"Kind of surreal to think sometimes that we're playing for the same franchise wearing the same number," Morneau said. "Not too many people get to do that. I like to compare it to everyone who grew up and played basketball and watched Michael Jordan and wanted to wear No. 23. For me it was the same kind of thing for baseball."

Worth noting

• LaTroy Hawkins secured his third save in three games to close out Monday's 3-2 victory over the Giants, the second time he's accomplished the feat this year. Weiss said he's been impressed with Hawkins' ability to perform at the age of 41, converting 21 of 22 possible save chances.

"We have a lot of confidence when Hawk is on the mound," Weiss said. "I wish he had more save opportunities than he's had this year, but whenever he's been in that position, he's been close to perfect."

Alex Espinoza is a contributor to MLB.com. Cody Ulm is an associate reporter for MLB.com.

This story was not subject to the approval of Major League Baseball or its clubs.