Daisuke Matsuzaka will not pitch as scheduled on Tuesday after getting a cortisone injection. (AP)

Right-hander Daisuke Matsuzaka had a cortisone shot in his right trapezius muscle in his upper back, manager Bobby Valentine told reporters, and he will not make his scheduled start on May 22. That almost certainly means that he will be shut down for at least seven days, thus permitting the Red Sox to start a fresh 30-day rehab clock for him on a minor league rehab assignment. Matsuzaka’s initial rehab assignment was slated to end on Wednesday.

Matsuzaka appeared, for much of the spring, to be well ahead of schedule in his rehab from Tommy John surgery. He suffered no setbacks after undergoing the procedure in June 2011, to the point where the Sox thought he might be back in the majors in less than a year.

That is no longer the case. Hist stuff was inconsistent en route to a 4.62 ERA over five minor league rehab starts. Though he struck out 22 and walked six in 25 1/3 innings, he also got shelled for six homers.

The fact that Matsuzaka is not available to the Sox in the near term underscores the tenuous depth of the team’s rotation. Matsuzaka is injured. So is Aaron Cook, though the sinkerballer seems likely to commence a minor league rehab assignment soon. Beyond those two, the team’s rotation options (should either injury or poor performance necessitate another starter) include pitchers such as Ross Ohlendorf and Justin Germano, pitchers with big league experience but who have been showing less-than-dominating stuff against Triple-A hitters.

That reality looms over conversations about whether to move Daniel Bard or Clay Buchholz out of the rotation if either struggles. For now, especially until Cook can return, the Sox face a question of what alternatives they have.

TRIPLE-A PAWTUCKET RED SOX: 6-3 LOSS AT NORFOLK (ORIOLES)

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– At the time that the Sox moved Alex Wilson into the bullpen, their major league bullpen was in a state of some crisis. Since then, however, the group has stabilized en route to the lowest bullpen ERA of any team in the majors in May. That being the case, the Sox have been able to proceed at a gradual pace with the right-hander, in deference to the absence of a pressing team need at the moment, the team’s depth (Mark Melancon, Clayton Mortensen and Junichi Tazawa have all been dominant this year, and all are on the 40-man roster) and the fact that Wilson himself has yet to perform at a level to force his way onto the big league roster.

On Sunday, Wilson allowed a run on three hits and a walk while striking out two. Now almost four weeks into his conversion from the rotation to the bullpen, he has remained on a scheduled progression, as he has had at least two days of rest before each of his relief appearances. He is 3-0 with a 3.29 ERA, 16 strikeouts (10.5 per nine innings) and six walks (4.0) and a WHIP of 1.54. He has just one outing in which he hasn’t permitted a baserunner (an outing in which he retired both of the batters he faced), that having come on April 28.

For now, the short- and long-term interests of the team suggest that Wilson develop as a reliever in the controlled setting afforded by the minors. At some point, the reins will come off, but that time has yet to arrive.

– Mark Melancon proved human in Triple-A, giving up his first walk (indeed, he issued two) and run (on a double) in his 14th appearance for Pawtucket. Still, he now has a 22-to-2 strikeout-to-walk ratio and a 0.64 ERA in his 14 games.

– Catcher Ryan Lavarnway entered Sunday’s game after a near-callup in Philadelphia, going 1-for-3 with a single to extend his hitting streak to eight games. The 24-year-old had not played since Thursday, and was on call in Philadelphia due to the health questions surrounding Jarrod Saltalamacchia after the Sox’ primary catcher required stitches after taking a deflected foul ball off the ear.

– Third baseman Kevin Youkilis had Sunday off. He is expected to play all nine innings on Monday, and barring a setback, that could prove his last rehab game with the PawSox.

DOUBLE-A PORTLAND SEA DOGS: 11-7 LOSS VS. BINGHAMTON (METS)

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– Bryce Brentz continued his scorching stretch, going 4-for-5 with a double to boost his average for the season .302 with a .342 OBP, .456 slugging mark and .798 OPS. The four-hit game — Brentz’s second in his last seven games — boosted his average over .300 for the first time since the third game of the year. Brentz is now hitting .426 (26-for-61) in May, the fourth best average in all of minor league baseball this month and tops among all Double-A players. Even so, with 16 strikeouts in 61 at-bats, his incredible performance does represent something of a mirage based on a ridiculous batting average on balls in play rate of .548.

– Chris Balcom-Miller walked five batters for the third time in his nine starts, with predictable ineffectiveness resulting. The right-hander allowed five runs (three earned) on four hits in four innings, and he now has more walks (27) than strikeouts (23) this season. Balcom-Miller has walked more batters than any other pitcher in the Eastern League, and his 1.66 WHIP is third-worst in the league. Despite his struggles to stay in the strike zone, however, Balcom-Miller’s rate of 2.95 groundouts per flyout is the best in the Eastern League. He seemingly represents a pitcher whose power sinker has enough bite that it can prove difficult to command.

– Reynaldo Rodriguez went deep for the eighth time in May, tying a Sea Dogs franchise record for the month, a standard previously achieved by Ryan Lavarnway, Kevin Millar, John Hattig and John Roskos.

HIGH-A SALEM RED SOX: 3-2 WIN VS. FREDERICK (ORIOLES)

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– Brandon Workman continued a strong start to his season with Salem. The big right-hander allowed two runs in six innings, striking out seven and walking one. For the year, he is now 2-1 with a 3.52 ERA, 35 strikeouts and eight walks in 30 2/3 innings. He’s showing higher strikeout rates (10.4 per nine innings) and better groundball rates (1.52 groundouts per flyout) this year than he did in 2011 in Single-A Greenville, where he had 7.9 strikeouts per nine innings and 0.92 groundouts per air out.

Workman has a better pitch mix now than he did when he started his pro career as a second-round selection of the Sox out of the University of Texas in the 2010 draft. The Red Sox made him abandon his cutter — a devastating pitch at the college level — at the outset of his professional career, wanting him instead to emphasize his curveball as his primary secondary pitch while also learning to work off of his fastball and to incorporate his changeup.

Once he’d made enough progress with his curve, the team let the 23-year-old start working his cutter back into the mix, and he’s been eliciting swings and misses with his fastball, curve and cutter this season. His fastball — which sits at 93-94 mph and tops out at times at 96 — has been overpowering at times. In his last four starts, he has 27 strikeouts in 20 1/3 innings.

He profiled as a bullpen arm coming out of Texas, but increasingly, with the development of his curve, there’s a growing potential for him to emerge as a big league starter. Certainly, his sturdy frame suggests an ability to take on a starter’s workload.

“He’s a horse,” said farm director Ben Crockett.

The right-hander is old for the level, and his experience at an elite college program suggested that he could have competed at Salem in 2011, but the Sox elected to put him in Greenville to acclimate to the five-day routine and also to rework his pitch mix. That being the case, the better measure of his abilities will probably be taken at a higher level. All the same, the stuff that the pitcher is showing now

– While Jackie Bradley Jr. has commanded the lion’s share of attention for his offense in Salem, teammate Travis Shaw continues to show a similarly advanced approach. The son of former big league closer Jeff Shaw, Travis Shaw drew three walks on Sunday, and he now has a .348 average (second-best in the Carolina League behind Bradley’s .373) with a .423 OBP that ranks third and a .934 OPS that ranks fifth.

Shaw, 22, was taken by the Sox in the ninth round of the 2011 draft, a spot in which he was available because his defense likely limits him to first base and he doesn’t have the present power characteristic of that position. But he has an advanced approach and good command of the strike zone, traits that make it possible that the 6-foot-4, 225-pound left-handed swinger could grow into power.

The reality is that ninth-round picks come with flaws. In the case of Shaw, the Sox identified a player who already does some things very well in a batter’s box (hitting for average, commanding the strike zone) while hoping that his plate intelligence and aptitude will allow him to develop into more of a power hitter down the road. If that happens, then Shaw will represent a terrific value find at a stage of the draft where big leaguers are typically hard to come by.

– Salem closer Michael Olmsted recorded his ninth save with three punchouts in the ninth, giving him 22 (against three walks) in 16 innings this year, good for a rate of 12.4 per nine innings. That follows a 2011 season in which Olmstead struck out 48 (and walked 10) in 32 1/3 innings between the Gulf Coast League and Greenville.

Olmsted is 25, so old for the level, though there are extenuating circumstances to the fact that he’s in High-A at an age when most players are a couple years removed from that level. He did not pitch with an MLB affiliate between 2008-11, as his career with the Mets (who drafted him in the ninth round in 2007) was derailed by Tommy John surgery. He missed 2009, ended up spending 2010 in the Japanese minor leagues (he did pitch in three NPB games with Fukuoka) before the Sox signed him at a tryout for the independent Golden League in May 2011.

His age alone means that Olmsted faces an uphill battle to get on a major league track. Still, he can run his fastball (typically in the low-90s) up to 95 and has a decent slider that’s helped the gigantic right-hander (listed at 6-foot-6 and 245 pounds, he’s certainly larger than that) strike out well over a batter an inning in the last two years. Since signing with the Sox, he’s gotten loads of strikeouts, has been stingy with walks and, in 48 1/3 innings over his two years with the Sox, he hasn’t given up a homer.

SINGLE-A GREENVILLE DRIVE: 6-5 WIN VS. WEST VIRGINIA (PIRATES)

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– Left-hander Miguel Pena struck out seven and walked none, continuing an attacking style of pitching that has made him extremely effective to date. Though he gave up seven hits and three runs (both the second largest yields he’s had this year), his 7.33 strikeouts per walk this year is second to only Matt Barnes among Red Sox starters this year.

– First baseman Boss Moanaroa went 2-for-3 with a double and a walk, improving his line to .274/.414/.425/.839. After collecting just four extra-base hits (and no doubles!) in his first 30 games, Moanaroa has four extra-base hits in his last five contests, including three doubles.

LINKS

– Tim Britton of the Providence Journal examines the difference in Salem left-hander Drake Britton from a year ago. Britton (Drake, that is) is enjoying his most sustained success in his year-plus in the Carolina League. The two Brittons also discussed the significant development of the pitcher’s changeup this season. No word on whether the two took the time to discuss Britons, Linda Poovey‘s excellent tome, or if they were too deeply ensnared in Poe’s veil of the soul to entertain the baser art of non-fiction.

– PawSox broadcaster Steve Hyder caught up with former Red Sox minor league manager and big league coach Ron Johnson, who is now managing the Orioles’ Triple-A affiliate. Johnson expresses enthusiasm for his new gig (for which he was hired by former Sox GM Dan Duquette), and also says that his daughter Bridget, who lost her leg when a car hit her while she was riding a horse, is doing extremely well, and in fact she’s riding once again. Her horse is named “Youkie,” after Sox infielder Kevin Youkilis, who bought the horse for the family.

– Jose Iglesias talks with PawSox play-by-play man Aaron Goldsmith about his swings of fortune. After a month of April in which he was hitting the ball hard without results, Iglesias is now being rewarded with much better results that have seen his numbers surge in May. “Baseball is a roller coaster,” Iglesias said. “You go up, you go down. The important thing is to be on the cart.”