But a healthy Elarton is looking forward to the game.
"I am actually kind of excited that I am pitching against the Yankees, because I have had success against them before," he said. "If I am going to come back to a challenge, it might as well be a big challenge. I am just going to go out there and just go to battle with them."
Elarton posted only one quality start in five rehab outings but felt stronger and healthier than he has been "in a long time." The veteran right-hander had elbow surgery last August and returned in mid-May. He went 2-3 with a 9.17 ERA in eight Major League outings before going on the disabled list in mid-June with a foot sprain.
"I feel stronger than I felt than when I went on the DL," he said. "Obviously the numbers aren't there, but I don't take any stock in rehab numbers. I feel positive and I am looking forward to tomorrow."
Even if it's not shown in the results, his delivery, command and durability have all improved during the rehab outings.
"Consistency in delivery has been the main thing," he said. "The last thing to come after surgery is command, and the command of my pitches while I have been on the DL has gotten better. My pitches have gotten a little bit sharper and maybe I have a little bit more velocity."
Pena Sr. returns: Current Yankees first-base coach and former Royals manager Tony Pena Sr. came to Kauffman Stadium for the first time this season. He received hugs from Royals players and personnel, including John Buck.
But he spent several minutes talking with one player, a player he hasn't seen since Spring Training -- his son, Tony Pena Jr.
In the spring, TJ (as he is called by many friends) was a backup in the Braves' organization. But he received new life when he was traded to the Royals at the end of Spring Training and has enjoyed a fine season, posting a .284 average and terrific glovework as the Royals' everyday shortstop.
"It's a good thing because he has a chance to play every day," the elder Pena said. "I don't think he ever would have had the chance with the Braves, with [Edgar] Renteria playing. He's doing well."
This marked the first time Pena saw his son play in a Major League game -- and his son collected the first hit off Roger Clemens in the third inning Monday night.
"It means a lot," Pena Jr. said. "This is the first chance he gets to see me play in the big leagues. It is going to be real fun for both of us. He told me that he is proud of me and keep going out there no matter what and have fun."
Pitching staff strong: The Royals are 14-8 in their last 22 games and carry a Major League best 3.36 ERA since June 23. The bullpen has also been terrific, posting a 2.15 ERA in that span. Royals manager Buddy Bell, though, would like to see more innings from his starters, especially with the lack of off-days on the upcoming schedule.
The team went 5-4 on its nine-game road swing through Cleveland, Boston and Detroit but only received two quality starts.
"We have to rely on our pitching, as do all good teams," Bell said. "We have to get more more quality starts and we have to get more innings. We have been lucky because we have had a couple of off-days and we have been able to give our bullpen a rest, but we can't keep going into the next day with the previous day giving us four or five innings. We just can't do that."
Butler continues to hit: Billy Butler has been one of the best hitters in baseball since the All-Star break. Among American League hitters with at least 25 at-bats, Butler's .444 second-half average is tied for second with the Devil Rays' B.J. Upton and ranks only behind the Indians' Ryan Garko (.571) entering play Monday.
"He can hit," Bell said. "He can really, really hit."
Bunts: The Royals have won five of their last six home series. ... Bell actually faced Clemens in his playing career, going 1-for-4: "I don't remember too much about it," he said. "He might be the greatest right-handed pitcher of all-time, and I hope that he has an off-night tonight." Several of the Royals, including Butler, weren't even born when Clemens came to the Majors. ... Broadcaster Denny Matthews will be honored in ceremonies Tuesday night. Matthews, the 39-year voice of the Royals, will enter the Hall of Fame this weekend in Cooperstown. ... Tuesday also marks the 24th anniversary of the Pine Tar game between the Yankees and the Royals. George Brett pine tar T-shirts will be distributed to the first 20,000 fans.
Royals Rundown: Triple-A Omaha won, 8-5, over Memphis. Angel Berroa drove in four runs on three hits, including a two-run homer. Joey Gathright finished with two hits, two stolen bases and three runs. Ryan Shealy continued his rehab assignment and went 1-for-4 with a run. He is 3-for-13 for Omaha since he rejoined the club. Neal Musser picked up his fourth save and has now worked 35 1/3 scoreless innings for the O-Royals. ... Double-A Wichita won, 8-1, over Springfield. Carlos Rosa (4-6, 5.23 ERA) tossed five innings of one-run ball, and Kila Kaaihue had three hits. Jorge Padilla (.358 average) and Adam Greenberg homered.
Class A Wilmington won, 6-3, over Lynchburg. Tyler Chambliss tossed five innings of one-run ball and won for the third time for Wilmington. ... Class A Burlington lost, 5-3, to West Michigan. Edward Cegarra allowed two runs in 5 1/3 innings. ... Advanced Rookie League Idaho Falls lost, 7-5, to Helena. Anthony Seratelli had two hits, a stolen base and a run scored. He is second in the Pioneer League with 11 stolen bases. ... Rookie League Burlington lost, 1-0, to Danville. Brian Gausman worked five innings of one-run ball but took the loss. ... Rookie League Arizona lost, 6-0, to the Arizona Giants. Peter Hodge Nielsen, the Royals' No. 4 pick in the 2007 First-Year Player Draft, allowed three runs and seven hits in four innings. Nielsen is 1-3 but has a 2.96 ERA and a 21-8 strikeout to walk ratio.
Player of the day: Kaaihue. The Wranglers first baseman had a three-hit night, his first multi-hit game since July 13. Overall, Kaaihue, the Royals' 15th-round pick in the 2002 Draft, is batting .252 with four homers and 13 RBIs this season.
Coming up: Elarton makes his first start since June 13 when he faces Yankees righty Chien-Ming Wang (10-5, 3.44) in the second contest of the four-game set. First pitch is set for 7:10 p.m. CT.
Conor Nicholl is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.