BRADENTON, Fla. -- Pirates third baseman Pedro Alvarez has been sidelined temporarily by discomfort in his left knee, which he will rest through the weekend.

On the alternate-day schedule of regulars, Alvarez was not due to be in Friday's lineup against the Tigers. He got an extended layoff, however, with the club announcing that Alvarez had been removed from Wednesday's game with "inflammation and discomfort in the left knee."

"I think he did it more or less running, when he hit a bag or landed a step behind a bag," manager Clint Hurdle theorized.

Alvarez has struggled offensively this spring and is hitless in his last 13 at-bats, including eight strikeouts.

Casey McGehee drew a scheduled start at third on Friday and reached base as a hit batter before Matt Hague homered for the Bucs' lone runs. The beneficiaries of Alvarez's absence will be Josh Harrison and Yamaico Navarro, who will get extended playing time at third as they battle for a reserve role.

Hague could also pick up some extra innings there but, as Hurdle said, "His bat is giving him a chance. He's not going to make the team on defense -- not that he's bad, but he's a first baseman trying to play third."

Morton feels ready to take the mound

BRADENTON, Fla. -- The Pirates appear hopeful of Charlie Morton being able to jump into their rotation at the first need for a fifth starter, which will not arise until April 15.

Morton himself had more aggressive plans after being in admirable command through his four-inning shutout stint on Friday against the menacing Tigers.

"I'm good. I want the ball," Morton said, and it was clear he meant he wanted it no later than April 11, for the Pirates' fifth game of the season.

Morton needed 55 pitches to get through his four innings of two-hit ball. The day before, Jeff Karstens, set for his first regular-season start on April 7 as the No. 2 man in the rotation, had thrown 89 pitches.

"So maybe I'm still a game behind the others. I can pick that up at the end of Spring Training," said Morton, who figures to have one more start remaining in Florida and also start one of the two exhibitions in Philadelphia.

Asked whether Morton remained in consideration to start the fifth game of the season, manager Clint Hurdle said, "We're still having those talks. We aren't on any pressing timetable. We're considering what we need to do to take care of everyone and win-win across the board."

The Pirates have scheduled off-days after the first and third games of the season. If Morton does go in the fifth game, Opening Day starter Erik Bedard would make his second start on six days' rest.

Worth noting

• The Tigers' first McKechnie Field appearance in two years drew a sellout crowd of 6,552, the Pirates' sixth of the spring. The club has five home dates remaining to top its Grapefruit League record of seven sellouts, in both 2007 and 2008.

• Saturday will be a red-letter day in Ryota Igarashi's bid to make the Pirates bullpen. He is scheduled to work another inning against the Astros, the first time he will have pitched in back-to-back games following his one shutout inning on Friday against Detroit. "I thought he was again good today," manager Clint Hurdle said of the non-roster right-hander from Japan. "He's still in the competition, battling, doing well."

• Matt Hague has nine hits -- including three of his team-leading four homers -- in his last 17 at-bats, raising his average to .438.

• Saddest part of Friday's six-run outburst in the ninth inning that gave the Tigers the 7-2 win: It deprived Anthony Norman of some serious props. The 27-year-old center fielder, one of several Minor Leaguers called up for the game, made a sensational diving catch of Chad Wright's liner to keep the tying run at second with one out -- but then the Tigers erupted to make the robbery moot.