ST. PETERSBURG, Fla. — Volatile Kansas City outfielder Jose Guillen got into a heated clubhouse exchange with pitching coach Bob McClure prior to Saturday night's game, knocking over chairs before several Royals stepped in to separate them.

Guillen and McClure argued face-to-face, but no punches were thrown. Guillen, who unleashed a profanity-filled tirade against his teammates in May, declined to comment on the incident and started against Tampa Bay.

It was the third locker room altercation in the majors in the last 10 days — none of them pitted player vs. player. Pitcher Shawn Chacon threw down Houston general manager Ed Wade and Boston slugger Manny Ramirez reportedly shoved a team official.

Guillen was sitting at a table by his locker when he toppled over a chair and made a comment in Spanish. After a teammate attempted to calm him down, Guillen appeared to get more agitated, tossed over another chair and said, "Coaches don't need to be all up in our ... business."

McClure, who was sitting at his locker, turned around and said, "Jose, if you're talking about me, then you need to shut ... up."

Guillen then knocked over another chair, yelled at McClure and confronted the coach.

Guillen told McClure he wasn't talking about him and wasn't being disrespectful toward the coach. Guillen added he didn't appreciate McClure telling him to be quiet.

Royals manager Trey Hillman was talking with reporters in the dugout when the exchange took place.

Hillman later sat in the dugout with Guillen for a couple minutes during batting practice and they walked together to the clubhouse. Hillman declined to comment about the dustup, saying all clubhouse matters would be handled internally.

JENKS HAS TESTS ON BACK: Chicago White Sox closer Bobby Jenks underwent an MRI and a CT scan on Saturday to determine the cause of soreness below his left shoulder in his upper back.

The tests came back negative, and the right-handed Jenks hopes to be available beginning Tuesday when the White Sox open a series in Kansas City.

Jenks, who is 2-0 with a 1.95 ERA and 18 saves in 21 opportunities, has not pitched since Sunday.

TULOWITZKI RETURNS TO DL: This trip for the 15-day disabled list cuts a little deeper for Troy Tulowitzki and the Colorado Rockies.

Just three weeks after returning from a torn thigh tendon that cost him 46 games, the Rockies' enigmatic shortstop sliced his right palm when he pounded his maple bat into the ground in frustration and it shattered. The accident occurred Friday night after he was replaced by Omar Quintanilla in the seventh inning.

"Yeah, it's tougher to take," Tulowitzki said Saturday of his return to the DL. "The other injury was baseball-related. You're out there on the field, going all out. And this one's kind of a stupid injury that I could have prevented."

Maple bats are the subject of a major league investigation because of their tendency to shatter when they break, unlike the softer ash bats, which usually just crack.

"I don't think that matters. I think ash would have done the same thing," he said.

"I looked at the cut and it looked pretty bad," added Tulowitzki, who expects to be out two weeks. "It was a scary moment."

WEAVER SIGNS WITH TRIBE: The Cleveland Indians signed free agent pitcher Jeff Weaver to a minor league contract on Saturday, giving the veteran a shot at making his sixth big-league team. The right-handed Weaver will report to Triple-A Buffalo of the International League.

The 31-year-old Weaver is 93-114 with an ERA of 4.72 in 284 appearances over nine seasons from 1999-2007. He's pitched for Detroit, the New York Yankees, Los Angeles Dodgers, St. Louis and Seattle. He had a career-best 14 wins for the Dodgers in 2005 and won three games for the World Series champion Cardinals in the 2006 postseason.

OSWALT HAS MORE HIP PAIN: Houston Astros pitcher Roy Oswalt returned to Houston on Saturday after experiencing more discomfort in his strained left hip.

Oswalt was examined by Dr. Mike McCann in Houston on Saturday and is expected to rejoin the team in Atlanta on Sunday. On Friday, he felt more pain in the hip when he tried to throw on flat ground.

"He just tried to put a little more into his throw and it just didn't feel good," manager Cecil Cooper said. "I don't think you can take any chances with Roy, he means too much."

Oswalt will try to throw on flat ground again on Monday and throw in the bullpen on Tuesday.The Astros did not announce results of Saturday's examination and have not announced when Oswalt will return to the rotation.