That would be Rashard Mendenhall, who rushed for 165 yards while filling in for Parker last week.
"But me being a competitor, I want to come back," Parker said. "I mean, if somebody's playing ball, and playing at a high level at your position, you want to play and compete against him. He definitely got me up and ready for the challenge."
As soon as Parker is healthy enough, the challenge will be on. In one corner is Mendenhall, 22, last year's No. 1 draft pick who flashed hints of power and speed in the fourth game last year against the Baltimore Ravens before Ray Lewis broke his scapula.
Parker, 29 on Nov. 11, has been the starter since 2005, but has been plagued with injuries since late 2007 and is in the last year of his contract.
"Willie's more spontaneous," right tackle Willie Colon said when asked to compare the two backs. "Sometimes he'll stay on track, sometimes he doesn't, but everybody knows he likes it outside. Mendenhall does a great job of following his track and hitting it where it needs to be hit. He's become a real good downhill runner. If you watch the tape, it looks like he's getting hit, but he's delivering a lot of blows with the ball."
Mendenhall ran inside and also bounced it outside against San Diego last Sunday. He caught two passes and blocked extremely well. On one pass play, he hit a blitzing Kevin Burnett so hard the linebacker didn't get up until after the whistle.
What did Mendenhall feel was the most satisfying aspect of his performance?
"Other than the win," he said, "I'd say just being able to be out there, and just watching the line blocking and how hard they tried when you inspire them, just things like that."
Did Mendenhall feel he inspired the line?
"I would think so. I guess so," he said. "He was definitely motivated," said Parker. "He got the chance and all eyes were on him. A lot of people were saying a lot of negative things about him and he went in and hit it. I told him from the start that's the name of the game, that's the game we play. You don't have to answer questions until you play, and I think he answered a lot of questions."
Parker said his injury is more severe than the turf toe injury he'd suffered earlier in his career.
"Your toe holds 80 percent of your body weight, as far as agility and everything, so I just have to be smart," he said. "It's kind of worse than the one I had before, but it feels a lot better today."
TROY IN LIMITED WORK
Strong safety Troy Polamalu wore a brace on his left knee and gingerly participated in his first practice since spraining his MCL in the opening game. Polamalu participated with the scout team in 7-on-7 drills only.
After missing three games, he's hoping to make his return at Ford Field in Detroit.
"I don't want him to," free safety Ryan Clark said of Polamalu playing his first game on an artificial surface (FieldTurf). "I tore my PCL a few years ago and it was tough to run on. It's a pounding. Some of them aren't very fluffy, so it's hard.
"You know Troy, though; he's a competitor. If he can come back this week, he is. But, me personally, I'd rather have him for the last 10, or the last stretch, rather than him come out and injure himself again and set himself back."
FOOTE THE LOUDMOUTH
Lions middle linebacker Larry Foote and Parker used to have lockers on opposite sides of an entrance way in the Steelers' locker room. Parker was asked about his former neighbor, and he didn't hold back.
"He's a loudmouth," Parker said. "He's a loudmouth, man. With me having him right beside me, I caught hell every day. He'd pick on the way I dressed, everything, all the little things."
Parker didn't pause, though, when he added: "I do miss him. He's definitely a friend for life."
Foote's old partner with the Steelers, James Farrior, said Foote was a terrific trash-talker on the field as well.
"He's the best in the business," Farrior said. "Him and Joey (Porter) taught me the art of trash-talking. With those two guys, especially Foote, I came a long way."
Farrior also holds immense respect for Foote, who asked for his release from the Steelers when he realized the coaching staff planned to give his job to former No. 1 pick Lawrence Timmons. Foote went back home to play for the hapless Lions, where he's the runaway tackles leader and is attempting to lead a massive turnaround.
"It says a lot about his character," Farrior said. "He's a guy that never shies away from a challenge, and that was definitely a humongous challenge for him to go to a team that was 0-16 and try to be a part of the rebuilding process. I think that defense looks a little different with him out there. He's been out there making plays. I think he's been the catalyst, the leader, out there on defense. You can tell the difference."