It’s amazing just how unforgiveable a loss to Illinois can be.

Take Oct. 23’s 9-overtime debacle away, and Penn State is probably a top-15 team rather than an unranked one. There’s pain but no shame in losing to teams ranked No. 3 (Iowa), No. 5 (Ohio State) and No. 9 (Michigan) by the AP at the time of the games.

But the 20-18 Homecoming loss to the Illini left the Lions chasing lost respect that couldn’t be regained against Rutgers, despite a dominating 28-0 victory last week.

This week’s game in another story, though. Michigan State (9-2, 6-2) is no longer a Big Ten or Playoff contender, but the program is No. 12 in the CFP rankings and just announced a 10-year extension for Mel Tucker that tops the one James Franklin signed a day earlier.

These are 2 committed programs, battling over the same B1G East turf — along with Michigan — to be first little brother to Ohio State. That’s the first step in ever catching the Buckeyes, and Penn State has held that ground for the bulk of Franklin’s 8-year tenure.

Coming off its 2nd B1G shutout of the season despite a flu-depleted roster, the Lions (7-4, 4-4) appear committed to finishing strong. Going into East Lansing and knocking the Spartans completely back into reality would raise Penn State’s waning national stature.

There’s a good chance it will happen, as oddsmakers list overachieving MSU as a 1.5-point underdog coming off its 56-7 thrashing at the hands of OSU.

Here’s why Penn State is in great shape heading into Saturday’s 3:30 ET kickoff on ABC:

Lions are committed

PSU’s best offensive player, Jahan Dotson, and 4 key defensive players have all committed to the Reese’s Senior Bowl. It stands to reason that players committed to a February exhibition won’t sit out real games to avoid injury prior to the NFL Draft. In addition to Dotson, DE Arnold Ebiketie, LB-DE Jesse Luketa, CB Tariq Castro-Fields and S Jaquan Brisker should be suiting up a couple more times for the Nittany Lions.

Quarterback Sean Clifford, recovered from a flu bug that knocked him out of the Rutgers game early, is expected to start Saturday as he has every game this season. The Lions should have their full complement of players available for the regular season finale.

MSU’s defense is terrible

Out of 130 FBS teams, Michigan State ranks 120th in total defense and dead last against the pass. And it has gotten progressively worse as the season has worn on. It allows 339.9 passing yards per game, which is 33.6 per game more than the next worst team, New Mexico State.

The only thing the Spartans do well on defense is get after the quarterback. Their 34 sacks rank second in the B1G, just 1 sack behind Ohio State. That, obviously, is a concern for Penn State, whose offensive line has been the program’s Achilles heel all season long. But if the guys up front can slow up Jacub Panasiuk and the rest of MSU’s hard-chargers just a little bit, Clifford should have a field day.

Penn State’s defense is excellent

After last week’s performance, Penn State jumped up to No. 4 in the nation in scoring defense. It won’t catch Georgia, but could move up to No. 2 with another dominating effort.

MSU presents a challenge, for sure, with serious weapons in standout RB Kenneth Walker III and WRs Jayden Reed and Jalen Nailor. But all 3 of them were banged up either before or during the loss to Ohio State, so their status is up in the air. Several other key players are iffy as well, and MSU’s depth is less than impressive. QB Payton Thorne might not have much help.

Final thoughts, prediction

Penn State has some positive vibes going. True freshman Christian Veilleux emerged as the No. 2 quarterback with his solid relief effort against Rutgers. Franklin’s contract extension buys some stability and assures prized QB Drew Allar and the rest of the No. 5 recruiting class of 2022 will show up on campus. Dotson and other veteran players give every indication they intend to finish strong. A few younger players — most notably OL Landon Tengwall and WR Malick Meiga, both freshmen — have gotten into the mix.

Penn State will return to the top 25 in the CFP and AP rankings with a win, and that would bode well for this bowl season and beyond. It’s worth pursuing, and the Lions seem poised to give it their best shot.

Penn State 34, Michigan State 13