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8/23/2013 1:18 A.M. ET

Mujica has nagging back issue checked out

ST. LOUIS -- Cardinals closer Edward Mujica met with Dr. Clayton Skaggs late Thursday afternoon and was deemed unavailable to pitch in the team's series opener that evening due to lingering tightness in the right upper side of his back.

While St. Louis is encouraged by the fact that nothing is structurally wrong, Mujica said he may have to sit out at least one more night in order to mitigate the issue.

"It's bothering me just in my back, sometimes like in a nerve, just going through my muscles like a little fatigue," Mujica said. "We've just been working on it a lot and trying to get it ready to go."

Mujica pitched 1 1/3 innings and earned his 33rd save on Wednesday, but he was straining enough to warrant a mound visit from the trainer. The Cardinals had given Mujica three days off over the weekend due to what was described at the time as arm fatigue. Mujica noted on Thursday that he has been dealing with this muscle issue since making a two-inning appearance against the Pirates one week ago.

That was the third straight two-inning appearance Mujica had made.

"I felt it after the game ... and when I got in to Chicago, I just started feeling a little tightness in my neck, and when I went Tuesday, I started feeling it in the back," Mujica said.

If, while Mujica is sidelined, a situation arises to where the Cards need a fill-in closer, those duties would likely fall to Trevor Rosenthal. Rosenthal pitched a scoreless ninth with a four-run lead in Thursday's 6-2 win.

Asked about the immediate outlook for Mujica, manager Mike Matheny said the club remains "hopeful for [Friday]."

Westbrook could miss next start with stiff back

ST. LOUIS -- Right-hander Jake Westbrook may not make his next scheduled start on Monday due to lingering back stiffness, Cardinals general manager John Mozeliak revealed on Thursday.

Westbrook's struggles date further back than this back injury -- which Mozeliak said has been an issue for the last two weeks -- but the Cardinals are not ruling out some potential causation between Westbrook's recent pitching troubles and the back discomfort. The veteran starter threw 75 pitches in a 4 2/3-inning start on Wednesday. He gave up four earned runs on nine hits and a walk after being staked to a seven-run lead.

A decision on Westbrook's status for Monday could be determined as early as Thursday night, Mozeliak said. Westbrook, through a team spokesman, declined to address the injury in further detail.

"Clearly," Mozeliak said, "right now from a physical standpoint, we're hoping he can work through it."

Even if the back stiffness were to subside, it is not a given that Westbrook will start as scheduled. He has been inconsistent since coming off the disabled list in mid-June after a bout of right elbow inflammation, and the results over the past month have been especially troublesome for a team in the thick of a division race.

Westbrook is winless in his last five outings, and he has allowed 38 hits, 28 earned runs and 16 walks in those 26 innings. Opponents have hit .345 off him during that span, with three homers. Westbrook has struck out only 11.

"Obviously, if you're dealing with something physical, that has to be addressed first and foremost," Mozeliak said. "I think the performance as it stands in its own silo, you look at in terms of we need to try to put our best five [starters] out there, if possible. I do think from a medical standpoint, Westy is dealing with something. Now we have to determine what's the next best step for him."

As the Cardinals' rotation order stands now, Westbrook's next three starts would come against the Reds at home, the Pirates on the road and the Pirates back at Busch Stadium. The fact that all three would be against the two teams the Cardinals are trying to beat in the National League Central augments the necessity of sending out the starter they feel gives them the best chance to win.

Even when healthy, Westbrook has fared poorly against the Pirates throughout his career. In 15 games (11 starts) against Pittsburgh, Westbrook is 1-8 with a 4.98 ERA.

If Westbrook can't start on Monday, the Cardinals will pick a starter from a group that includes Michael Wacha, Tyler Lyons and Carlos Martinez. The spot starter is likely to be determined, in part, by how manager Mike Matheny has to use his bullpen between now and then. Both Wacha and Lyons are currently in that seven-man 'pen. Martinez is scheduled to start for Triple-A Memphis on Friday.

Finding help externally seems a long shot with the August waiver period nearly over. A dearth of players passing through waivers, the process of not being able to claim a player on waivers until every team with a worse record passes, and the asking prices for those players made available, Mozeliak said, have all limited the outside options.

Cards top prospect Taveras has ankle surgery

ST. LOUIS -- Cardinals top prospect Oscar Taveras underwent season-ending ankle surgery on Wednesday, during which a doctor cleaned up cartilage and repaired ligament damage.

The surgery had been scheduled a week ago after Taveras' most recent attempt to begin baseball activities stalled due to continued discomfort in his right ankle. He had been bothered by the injury since it occurred in a Triple-A game on May 12.

General manager John Mozeliak said that Taveras will wear a boot or cast on his right foot for the next eight weeks, after which the 21-year-old outfielder will begin physical therapy. That timeline almost certainly rules Taveras out for any exposure in winter ball, though the Cardinals do expect Taveras to be able to prepare fully for the 2014 season.

"Everything looks like he'll be ready to go by Spring Training, so that's encouraging," Mozeliak said. "I spoke with our medical staff, and they really felt like this was the best option for him."

Taveras, who was expected to be in the Majors before the end of 2013, was instead limited to 46 games in Triple-A this year. The outfielder batted .306 with a .341 on-base percentage and .462 slugging percentage. Taveras drove in 32 and scored 25 runs.

Worth noting

• After starting five straight games and six of seven since coming off the disabled list with a right knee sprain, Yadier Molina was out of the Cardinals' lineup for Thursday's series opener against the Braves. The Cards had indicated that they would be proactive in giving Molina days off during the catcher's first week back, but Mozeliak acknowledged that the organization has since "deviated from" that plan.

"I think with a player like him, he's going to have some say in whether he can go or not," Mozeliak said. "We welcome that type of feedback. In his case, the past few days have been fine for him, so from a medical standpoint, I don't see any restrictions."

• Left-hander Jaime Garcia said he is just days away from beginning his throwing program. Garcia underwent season-ending surgery on his left shoulder nearly three months ago. He has remained in St. Louis to do his rehab work and has recently begun to strengthen his arm with medicine ball exercises.

• Major League Baseball announced on Thursday that Cardinals Minor Leaguer Yoenny Gonzalez has been suspended without pay for 50 games after violating the Minor League Drug Prevention and Treatment Program. MLB's announcement did not specify for which substance Gonzalez tested positive.

Gonzalez, an eighth-round pick out of Central Florida Community College in the 2012 First-Year Player Draft, played 32 games with rookie-level Johnson City (Tenn.) this season. He batted .192 with four doubles, two triples and 10 RBIs. With less than 50 games remaining in the Minor League season, Gonzalez will finish serving his suspension in 2014.

• The Cardinals' four-game series against the Braves will showcase the two National League players currently leading the batting title race. Molina and Atlanta's Chris Johnson both entered Thursday with a .332 season average. Johnson, who has 131 hits in 394 at-bats, technically leads Molina when the two batting averages are carried out to the fifth decimal point. Molina is 10-for-27 since returning from the DL.

Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.