PEORIA, Ariz. -- Mark Prior's return answered his own questions about his arm, but created some about his effectiveness. Kerry Wood's comeback was far more reassuring to the Cubs.

Prior, who missed most of 2006 during a third consecutive season of injuries, started for the first time since August. He allowed three earned runs and got just four outs before Chicago manager Lou Piniella pulled his expected ace from the Cubs' 6-5 win over the Seattle Mariners on Monday.

"I just wasn't finishing my pitches," Prior said, after throwing 41 pitches -- 16 chest-high or higher.

"The most important thing for me is this is the first time in almost 2½ years I wasn't more worried about my arm than facing batters."

But Wood was dominant. Throwing 95 mph fastballs and sliders, the 2003 All-Star retired the Mariners in order in the fifth. He struck out Jose Guillen and threw 12 pitches, eight of them strikes.

The Cubs' former ace is trying to come back as a reliever following shoulder surgery on Aug. 31, 2005, that limited him to just four games last season.

Prior was scheduled to go two innings in his first spring start since 2005. Following a 25-pitch first inning that included two walks, pitching coach Larry Rothschild stood beside Prior and pantomimed an exaggerated followthrough toward the dugout floor.

After an errant fastball forced catcher Michael Barrett out of his crouch and into a reaching snag, Rothschild visited Prior on the mound. Mike Morse hit the next pitch into the left-center field gap for a double.

Jeremy Reed followed by hitting a 2-1 pitch 15 feet up the dark hitting background beyond straightaway center field, over the 410-foot sign.

"That was the only ball that I thought I threw well," Prior said.

That double -- one of three off Prior -- scored Kenji Johjima for a 2-0 lead. After No. 9 hitter Yuniesky Betancourt's hard, one-hop groundout, on a 1-0 pitch, Piniella replaced the 26-year-old right-hander with Ben Howard.

Prior sat on the dugout bench and threw his cap over his shoulder and into the back wall of the dugout. Howard then allowed Willie Bloomquist's RBI single, the third and final run charged to Prior.

Adrian Beltre, a one-time Los Angeles Dodger and one of the only Mariners to have faced Prior before in the National League, said "that was not the Prior I usually faced."

Beltre grounded out in his only at-bat against him.

"His fastball wasn't like before. It's obviously he's coming back from injury," said Beltre, who is 1-for-10 with a home run and five strikeouts against Prior in his regular-season career.

Piniella said that velocity -- some radar guns reported Prior's fastest pitches were 87 mph -- will come after Prior gets comfortable with simply pitching again.

"Obviously, he needs to throw the ball better. Let's be honest," Piniella said after Chicago's first win in four spring games. "But it's a start for Mark that he can improve on."

Prior said he wasn't happy with the way he threw, "but I'm looking at the bigger picture here."

"I was more happy I was able to get into a game," he said. "I'm not too worried about my command out there (yet). If I'm doing this three or four weeks from now, obviously that would be setting up a panic mode."

If Wood is doing this three or four weeks from now, the Cubs will be ecstatic.

"That's 95 miles per hour nice and easy," Piniella said, smiling. "After I saw him throw the first five or six pitches, I said, 'I had a good day already."'

Wood, 29, said his heart was racing and that he was initially "overamped" in his first game since June 6. He also said he has more energy after losing 25 pounds this winter through exercise and better eating, that his shoulder is healthy, and he's ready to restart his rise-and-fall career as a reliever.

"Starting is not even in my thought process," said Wood, who has 178 starts in 189 career games. "I may never start another game again, and if it's that's way I'm fine with it.

"I'm playing baseball. I can't complain."

Notes

• Ted Lilly, Chicago's $40 million free-agent acquisition, made his spring debut with two scoreless innings. He allowed one hit, a single by Reed, but then got a double play. "Kind of hit-and-miss," Lilly said. "I got away with a couple of pitches."
• RHP Miguel Batista, one of three new starters for the Mariners, pitched two scoreless innings and got two strikeouts before two walks that manager Mike Hargrove said was from fatigue.
• The contract renewal that RHP Felix Hernandez received from the Mariners last weekend is a split contract worth $420,000 for this season if Hernandez stays with Seattle, as expected. It's worth $204,000 if the 20-year-old is sent to the minor leagues. Hernandez has all but been announced as the opening-day starter.